// SPDX-License-Identifier: GPL-2.0-only
/*
 * kernel/workqueue.c - generic async execution with shared worker pool
 *
 * Copyright (C) 2002		Ingo Molnar
 *
 *   Derived from the taskqueue/keventd code by:
 *     David Woodhouse <dwmw2@infradead.org>
 *     Andrew Morton
 *     Kai Petzke <wpp@marie.physik.tu-berlin.de>
 *     Theodore Ts'o <tytso@mit.edu>
 *
 * Made to use alloc_percpu by Christoph Lameter.
 *
 * Copyright (C) 2010		SUSE Linux Products GmbH
 * Copyright (C) 2010		Tejun Heo <tj@kernel.org>
 *
 * This is the generic async execution mechanism.  Work items as are
 * executed in process context.  The worker pool is shared and
 * automatically managed.  There are two worker pools for each CPU (one for
 * normal work items and the other for high priority ones) and some extra
 * pools for workqueues which are not bound to any specific CPU - the
 * number of these backing pools is dynamic.
 *
 * Please read Documentation/core-api/workqueue.rst for details.
 */

#include <generated/deconfig.h>
#include <linux/export.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/init.h>
#include <linux/signal.h>
#include <linux/completion.h>
#include <linux/workqueue.h>
#include <linux/slab.h>
#include <linux/cpu.h>
#include <linux/notifier.h>
#include <linux/kthread.h>
#include <linux/hardirq.h>
#include <linux/mempolicy.h>
#include <linux/freezer.h>
#include <linux/debug_locks.h>
#include <linux/lockdep.h>
#include <linux/idr.h>
#include <linux/jhash.h>
#include <linux/hashtable.h>
#include <linux/rculist.h>
#include <linux/nodemask.h>
#include <linux/moduleparam.h>
#include <linux/uaccess.h>
#include <linux/sched/isolation.h>
#include <linux/nmi.h>
#include <linux/kvm_para.h>

#include "workqueue_internal.h"

enum {
	/*
	 * worker_pool flags
	 *
	 * A bound pool is either associated or disassociated with its CPU.
	 * While associated (!DISASSOCIATED), all workers are bound to the
	 * CPU and none has %WORKER_UNBOUND set and concurrency management
	 * is in effect.
	 *
	 * While DISASSOCIATED, the cpu may be offline and all workers have
	 * %WORKER_UNBOUND set and concurrency management disabled, and may
	 * be executing on any CPU.  The pool behaves as an unbound one.
	 *
	 * Note that DISASSOCIATED should be flipped only while holding
	 * wq_pool_attach_mutex to avoid changing binding state while
	 * worker_attach_to_pool() is in progress.
	 */
	POOL_MANAGER_ACTIVE	= 1 << 0,	/* being managed */
	POOL_DISASSOCIATED	= 1 << 2,	/* cpu can't serve workers */

	/* worker flags */
	WORKER_DIE		= 1 << 1,	/* die die die */
	WORKER_IDLE		= 1 << 2,	/* is idle */
	WORKER_PREP		= 1 << 3,	/* preparing to run works */
	WORKER_CPU_INTENSIVE	= 1 << 6,	/* cpu intensive */
	WORKER_UNBOUND		= 1 << 7,	/* worker is unbound */
	WORKER_REBOUND		= 1 << 8,	/* worker was rebound */

	WORKER_NOT_RUNNING	= WORKER_PREP | WORKER_CPU_INTENSIVE |
				  WORKER_UNBOUND | WORKER_REBOUND,

	NR_STD_WORKER_POOLS	= 2,		/* # standard pools per cpu */

	UNBOUND_POOL_HASH_ORDER	= 6,		/* hashed by pool->attrs */
	BUSY_WORKER_HASH_ORDER	= 6,		/* 64 pointers */

	MAX_IDLE_WORKERS_RATIO	= 4,		/* 1/4 of busy can be idle */
	IDLE_WORKER_TIMEOUT	= 300 * HZ,	/* keep idle ones for 5 mins */

	MAYDAY_INITIAL_TIMEOUT  = HZ / 100 >= 2 ? HZ / 100 : 2,
						/* call for help after 10ms
						   (min two ticks) */
	MAYDAY_INTERVAL		= HZ / 10,	/* and then every 100ms */
	CREATE_COOLDOWN		= HZ,		/* time to breath after fail */

	/*
	 * Rescue workers are used only on emergencies and shared by
	 * all cpus.  Give MIN_NICE.
	 */
	RESCUER_NICE_LEVEL	= MIN_NICE,
	HIGHPRI_NICE_LEVEL	= MIN_NICE,

	WQ_NAME_LEN		= 24,
};

///*
// * Structure fields follow one of the following exclusion rules.
// *
// * I: Modifiable by initialization/destruction paths and read-only for
// *    everyone else.
// *
// * P: Preemption protected.  Disabling preemption is enough and should
// *    only be modified and accessed from the local cpu.
// *
// * L: pool->lock protected.  Access with pool->lock held.
// *
// * X: During normal operation, modification requires pool->lock and should
// *    be done only from local cpu.  Either disabling preemption on local
// *    cpu or grabbing pool->lock is enough for read access.  If
// *    POOL_DISASSOCIATED is set, it's identical to L.
// *
// * A: wq_pool_attach_mutex protected.
// *
// * PL: wq_pool_mutex protected.
// *
// * PR: wq_pool_mutex protected for writes.  RCU protected for reads.
// *
// * PW: wq_pool_mutex and wq->mutex protected for writes.  Either for reads.
// *
// * PWR: wq_pool_mutex and wq->mutex protected for writes.  Either or
// *      RCU for reads.
// *
// * WQ: wq->mutex protected.
// *
// * WR: wq->mutex protected for writes.  RCU protected for reads.
// *
// * MD: wq_mayday_lock protected.
// */

///* struct worker is defined in workqueue_internal.h */

//struct worker_pool {
//	raw_spinlock_t		lock;		/* the pool lock */
//	int			cpu;		/* I: the associated cpu */
//	int			node;		/* I: the associated node ID */
//	int			id;		/* I: pool ID */
//	unsigned int		flags;		/* X: flags */

//	unsigned long		watchdog_ts;	/* L: watchdog timestamp */

//	struct list_head	worklist;	/* L: list of pending works */

//	int			nr_workers;	/* L: total number of workers */
//	int			nr_idle;	/* L: currently idle workers */

//	struct list_head	idle_list;	/* X: list of idle workers */
//	struct timer_list	idle_timer;	/* L: worker idle timeout */
//	struct timer_list	mayday_timer;	/* L: SOS timer for workers */

//	/* a workers is either on busy_hash or idle_list, or the manager */
//	DECLARE_HASHTABLE(busy_hash, BUSY_WORKER_HASH_ORDER);
//						/* L: hash of busy workers */

//	struct worker		*manager;	/* L: purely informational */
//	struct list_head	workers;	/* A: attached workers */
//	struct completion	*detach_completion; /* all workers detached */

//	struct ida		worker_ida;	/* worker IDs for task name */

//	struct workqueue_attrs	*attrs;		/* I: worker attributes */
//	struct hlist_node	hash_node;	/* PL: unbound_pool_hash node */
//	int			refcnt;		/* PL: refcnt for unbound pools */

//	/*
//	 * The current concurrency level.  As it's likely to be accessed
//	 * from other CPUs during try_to_wake_up(), put it in a separate
//	 * cacheline.
//	 */
//	atomic_t		nr_running ____cacheline_aligned_in_smp;

//	/*
//	 * Destruction of pool is RCU protected to allow dereferences
//	 * from get_work_pool().
//	 */
//	struct rcu_head		rcu;
//} ____cacheline_aligned_in_smp;

///*
// * The per-pool workqueue.  While queued, the lower WORK_STRUCT_FLAG_BITS
// * of work_struct->data are used for flags and the remaining high bits
// * point to the pwq; thus, pwqs need to be aligned at two's power of the
// * number of flag bits.
// */
//struct pool_workqueue {
//	struct worker_pool	*pool;		/* I: the associated pool */
//	struct workqueue_struct *wq;		/* I: the owning workqueue */
//	int			work_color;	/* L: current color */
//	int			flush_color;	/* L: flushing color */
//	int			refcnt;		/* L: reference count */
//	int			nr_in_flight[WORK_NR_COLORS];
//						/* L: nr of in_flight works */
//	int			nr_active;	/* L: nr of active works */
//	int			max_active;	/* L: max active works */
//	struct list_head	delayed_works;	/* L: delayed works */
//	struct list_head	pwqs_node;	/* WR: node on wq->pwqs */
//	struct list_head	mayday_node;	/* MD: node on wq->maydays */

//	/*
//	 * Release of unbound pwq is punted to system_wq.  See put_pwq()
//	 * and pwq_unbound_release_workfn() for details.  pool_workqueue
//	 * itself is also RCU protected so that the first pwq can be
//	 * determined without grabbing wq->mutex.
//	 */
//	struct work_struct	unbound_release_work;
//	struct rcu_head		rcu;
//} __aligned(1 << WORK_STRUCT_FLAG_BITS);

///*
// * Structure used to wait for workqueue flush.
// */
//struct wq_flusher {
//	struct list_head	list;		/* WQ: list of flushers */
//	int			flush_color;	/* WQ: flush color waiting for */
//	struct completion	done;		/* flush completion */
//};

//struct wq_device;

/*
 * The externally visible workqueue.  It relays the issued work items to
 * the appropriate worker_pool through its pool_workqueues.
 */
struct workqueue_struct {
	struct list_head	pwqs;		/* WR: all pwqs of this wq */
	struct list_head	list;		/* PR: list of all workqueues */

	struct mutex		mutex;		/* protects this wq */
	int			work_color;	/* WQ: current work color */
	int			flush_color;	/* WQ: current flush color */
	atomic_t		nr_pwqs_to_flush; /* flush in progress */
	struct wq_flusher	*first_flusher;	/* WQ: first flusher */
	struct list_head	flusher_queue;	/* WQ: flush waiters */
	struct list_head	flusher_overflow; /* WQ: flush overflow list */

	struct list_head	maydays;	/* MD: pwqs requesting rescue */
	struct worker		*rescuer;	/* MD: rescue worker */

	int			nr_drainers;	/* WQ: drain in progress */
	int			saved_max_active; /* WQ: saved pwq max_active */

	struct workqueue_attrs	*unbound_attrs;	/* PW: only for unbound wqs */
	struct pool_workqueue	*dfl_pwq;	/* PW: only for unbound wqs */

#ifdef CONFIG_SYSFS
	struct wq_device	*wq_dev;	/* I: for sysfs interface */
#endif
#ifdef CONFIG_LOCKDEP
	char			*lock_name;
	struct lock_class_key	key;
	struct lockdep_map	lockdep_map;
#endif
	char			name[WQ_NAME_LEN]; /* I: workqueue name */

	/*
	 * Destruction of workqueue_struct is RCU protected to allow walking
	 * the workqueues list without grabbing wq_pool_mutex.
	 * This is used to dump all workqueues from sysrq.
	 */
	struct rcu_head		rcu;

	/* hot fields used during command issue, aligned to cacheline */
	unsigned int		flags ____cacheline_aligned; /* WQ: WQ_* flags */
	struct pool_workqueue __percpu *cpu_pwqs; /* I: per-cpu pwqs */
	struct pool_workqueue __rcu *numa_pwq_tbl[]; /* PWR: unbound pwqs indexed by node */
};

//static struct kmem_cache *pwq_cache;

//static cpumask_var_t *wq_numa_possible_cpumask;
//					/* possible CPUs of each node */

//static bool wq_disable_numa;
//module_param_named(disable_numa, wq_disable_numa, bool, 0444);

///* see the comment above the definition of WQ_POWER_EFFICIENT */
//static bool wq_power_efficient = IS_ENABLED(CONFIG_WQ_POWER_EFFICIENT_DEFAULT);
//module_param_named(power_efficient, wq_power_efficient, bool, 0444);

//static bool wq_online;			/* can kworkers be created yet? */

//static bool wq_numa_enabled;		/* unbound NUMA affinity enabled */

///* buf for wq_update_unbound_numa_attrs(), protected by CPU hotplug exclusion */
//static struct workqueue_attrs *wq_update_unbound_numa_attrs_buf;

//static DEFINE_MUTEX(wq_pool_mutex);	/* protects pools and workqueues list */
//static DEFINE_MUTEX(wq_pool_attach_mutex); /* protects worker attach/detach */
//static DEFINE_RAW_SPINLOCK(wq_mayday_lock);	/* protects wq->maydays list */
///* wait for manager to go away */
//static struct rcuwait manager_wait = __RCUWAIT_INITIALIZER(manager_wait);

//static LIST_HEAD(workqueues);		/* PR: list of all workqueues */
//static bool workqueue_freezing;		/* PL: have wqs started freezing? */

///* PL: allowable cpus for unbound wqs and work items */
//static cpumask_var_t wq_unbound_cpumask;

///* CPU where unbound work was last round robin scheduled from this CPU */
//static DEFINE_PER_CPU(int, wq_rr_cpu_last);

///*
// * Local execution of unbound work items is no longer guaranteed.  The
// * following always forces round-robin CPU selection on unbound work items
// * to uncover usages which depend on it.
// */
//#ifdef CONFIG_DEBUG_WQ_FORCE_RR_CPU
//static bool wq_debug_force_rr_cpu = true;
//#else
//static bool wq_debug_force_rr_cpu = false;
//#endif
//module_param_named(debug_force_rr_cpu, wq_debug_force_rr_cpu, bool, 0644);

///* the per-cpu worker pools */
//static DEFINE_PER_CPU_SHARED_ALIGNED(struct worker_pool [NR_STD_WORKER_POOLS], cpu_worker_pools);

//static DEFINE_IDR(worker_pool_idr);	/* PR: idr of all pools */

///* PL: hash of all unbound pools keyed by pool->attrs */
//static DEFINE_HASHTABLE(unbound_pool_hash, UNBOUND_POOL_HASH_ORDER);

///* I: attributes used when instantiating standard unbound pools on demand */
//static struct workqueue_attrs *unbound_std_wq_attrs[NR_STD_WORKER_POOLS];

///* I: attributes used when instantiating ordered pools on demand */
//static struct workqueue_attrs *ordered_wq_attrs[NR_STD_WORKER_POOLS];

struct workqueue_struct *system_wq __read_mostly;
EXPORT_SYMBOL(system_wq);
//struct workqueue_struct *system_highpri_wq __read_mostly;
//EXPORT_SYMBOL_GPL(system_highpri_wq);
//struct workqueue_struct *system_long_wq __read_mostly;
//EXPORT_SYMBOL_GPL(system_long_wq);
struct workqueue_struct *system_unbound_wq __read_mostly;
EXPORT_SYMBOL_GPL(system_unbound_wq);
struct workqueue_struct *system_freezable_wq __read_mostly;
EXPORT_SYMBOL_GPL(system_freezable_wq);
struct workqueue_struct *system_power_efficient_wq __read_mostly;
EXPORT_SYMBOL_GPL(system_power_efficient_wq);
//struct workqueue_struct *system_freezable_power_efficient_wq __read_mostly;
//EXPORT_SYMBOL_GPL(system_freezable_power_efficient_wq);

//static int worker_thread(void *__worker);
//static void workqueue_sysfs_unregister(struct workqueue_struct *wq);
//static void show_pwq(struct pool_workqueue *pwq);

//#define CREATE_TRACE_POINTS
//#include <trace/events/workqueue.h>

//#define assert_rcu_or_pool_mutex()					\
//	RCU_LOCKDEP_WARN(!rcu_read_lock_held() &&			\
//			 !lockdep_is_held(&wq_pool_mutex),		\
//			 "RCU or wq_pool_mutex should be held")

//#define assert_rcu_or_wq_mutex_or_pool_mutex(wq)			\
//	RCU_LOCKDEP_WARN(!rcu_read_lock_held() &&			\
//			 !lockdep_is_held(&wq->mutex) &&		\
//			 !lockdep_is_held(&wq_pool_mutex),		\
//			 "RCU, wq->mutex or wq_pool_mutex should be held")

//#define for_each_cpu_worker_pool(pool, cpu)				\
//	for ((pool) = &per_cpu(cpu_worker_pools, cpu)[0];		\
//	     (pool) < &per_cpu(cpu_worker_pools, cpu)[NR_STD_WORKER_POOLS]; \
//	     (pool)++)

///**
// * for_each_pool - iterate through all worker_pools in the system
// * @pool: iteration cursor
// * @pi: integer used for iteration
// *
// * This must be called either with wq_pool_mutex held or RCU read
// * locked.  If the pool needs to be used beyond the locking in effect, the
// * caller is responsible for guaranteeing that the pool stays online.
// *
// * The if/else clause exists only for the lockdep assertion and can be
// * ignored.
// */
//#define for_each_pool(pool, pi)						\
//	idr_for_each_entry(&worker_pool_idr, pool, pi)			\
//		if (({ assert_rcu_or_pool_mutex(); false; })) { }	\
//		else

///**
// * for_each_pool_worker - iterate through all workers of a worker_pool
// * @worker: iteration cursor
// * @pool: worker_pool to iterate workers of
// *
// * This must be called with wq_pool_attach_mutex.
// *
// * The if/else clause exists only for the lockdep assertion and can be
// * ignored.
// */
//#define for_each_pool_worker(worker, pool)				\
//	list_for_each_entry((worker), &(pool)->workers, node)		\
//		if (({ lockdep_assert_held(&wq_pool_attach_mutex); false; })) { } \
//		else

///**
// * for_each_pwq - iterate through all pool_workqueues of the specified workqueue
// * @pwq: iteration cursor
// * @wq: the target workqueue
// *
// * This must be called either with wq->mutex held or RCU read locked.
// * If the pwq needs to be used beyond the locking in effect, the caller is
// * responsible for guaranteeing that the pwq stays online.
// *
// * The if/else clause exists only for the lockdep assertion and can be
// * ignored.
// */
//#define for_each_pwq(pwq, wq)						\
//	list_for_each_entry_rcu((pwq), &(wq)->pwqs, pwqs_node,		\
//				 lockdep_is_held(&(wq->mutex)))

//#ifdef CONFIG_DEBUG_OBJECTS_WORK

//static const struct debug_obj_descr work_debug_descr;

//static void *work_debug_hint(void *addr)
//{
//	return ((struct work_struct *) addr)->func;
//}

//static bool work_is_static_object(void *addr)
//{
//	struct work_struct *work = addr;

//	return test_bit(WORK_STRUCT_STATIC_BIT, work_data_bits(work));
//}

///*
// * fixup_init is called when:
// * - an active object is initialized
// */
//static bool work_fixup_init(void *addr, enum debug_obj_state state)
//{
//	struct work_struct *work = addr;

//	switch (state) {
//	case ODEBUG_STATE_ACTIVE:
//		cancel_work_sync(work);
//		debug_object_init(work, &work_debug_descr);
//		return true;
//	default:
//		return false;
//	}
//}

///*
// * fixup_free is called when:
// * - an active object is freed
// */
//static bool work_fixup_free(void *addr, enum debug_obj_state state)
//{
//	struct work_struct *work = addr;

//	switch (state) {
//	case ODEBUG_STATE_ACTIVE:
//		cancel_work_sync(work);
//		debug_object_free(work, &work_debug_descr);
//		return true;
//	default:
//		return false;
//	}
//}

//static const struct debug_obj_descr work_debug_descr = {
//	.name		= "work_struct",
//	.debug_hint	= work_debug_hint,
//	.is_static_object = work_is_static_object,
//	.fixup_init	= work_fixup_init,
//	.fixup_free	= work_fixup_free,
//};

//static inline void debug_work_activate(struct work_struct *work)
//{
//	debug_object_activate(work, &work_debug_descr);
//}

//static inline void debug_work_deactivate(struct work_struct *work)
//{
//	debug_object_deactivate(work, &work_debug_descr);
//}

//void __init_work(struct work_struct *work, int onstack)
//{
//	if (onstack)
//		debug_object_init_on_stack(work, &work_debug_descr);
//	else
//		debug_object_init(work, &work_debug_descr);
//}
//EXPORT_SYMBOL_GPL(__init_work);

//void destroy_work_on_stack(struct work_struct *work)
//{
//	debug_object_free(work, &work_debug_descr);
//}
//EXPORT_SYMBOL_GPL(destroy_work_on_stack);

//void destroy_delayed_work_on_stack(struct delayed_work *work)
//{
//	destroy_timer_on_stack(&work->timer);
//	debug_object_free(&work->work, &work_debug_descr);
//}
//EXPORT_SYMBOL_GPL(destroy_delayed_work_on_stack);

//#else
//static inline void debug_work_activate(struct work_struct *work) { }
//static inline void debug_work_deactivate(struct work_struct *work) { }
//#endif

///**
// * worker_pool_assign_id - allocate ID and assing it to @pool
// * @pool: the pool pointer of interest
// *
// * Returns 0 if ID in [0, WORK_OFFQ_POOL_NONE) is allocated and assigned
// * successfully, -errno on failure.
// */
//static int worker_pool_assign_id(struct worker_pool *pool)
//{
//	int ret;

//	lockdep_assert_held(&wq_pool_mutex);

//	ret = idr_alloc(&worker_pool_idr, pool, 0, WORK_OFFQ_POOL_NONE,
//			GFP_KERNEL);
//	if (ret >= 0) {
//		pool->id = ret;
//		return 0;
//	}
//	return ret;
//}

///**
// * unbound_pwq_by_node - return the unbound pool_workqueue for the given node
// * @wq: the target workqueue
// * @node: the node ID
// *
// * This must be called with any of wq_pool_mutex, wq->mutex or RCU
// * read locked.
// * If the pwq needs to be used beyond the locking in effect, the caller is
// * responsible for guaranteeing that the pwq stays online.
// *
// * Return: The unbound pool_workqueue for @node.
// */
//static struct pool_workqueue *unbound_pwq_by_node(struct workqueue_struct *wq,
//						  int node)
//{
//	assert_rcu_or_wq_mutex_or_pool_mutex(wq);

//	/*
//	 * XXX: @node can be NUMA_NO_NODE if CPU goes offline while a
//	 * delayed item is pending.  The plan is to keep CPU -> NODE
//	 * mapping valid and stable across CPU on/offlines.  Once that
//	 * happens, this workaround can be removed.
//	 */
//	if (unlikely(node == NUMA_NO_NODE))
//		return wq->dfl_pwq;

//	return rcu_dereference_raw(wq->numa_pwq_tbl[node]);
//}

//static unsigned int work_color_to_flags(int color)
//{
//	return color << WORK_STRUCT_COLOR_SHIFT;
//}

//static int get_work_color(struct work_struct *work)
//{
//	return (*work_data_bits(work) >> WORK_STRUCT_COLOR_SHIFT) &
//		((1 << WORK_STRUCT_COLOR_BITS) - 1);
//}

//static int work_next_color(int color)
//{
//	return (color + 1) % WORK_NR_COLORS;
//}

///*
// * While queued, %WORK_STRUCT_PWQ is set and non flag bits of a work's data
// * contain the pointer to the queued pwq.  Once execution starts, the flag
// * is cleared and the high bits contain OFFQ flags and pool ID.
// *
// * set_work_pwq(), set_work_pool_and_clear_pending(), mark_work_canceling()
// * and clear_work_data() can be used to set the pwq, pool or clear
// * work->data.  These functions should only be called while the work is
// * owned - ie. while the PENDING bit is set.
// *
// * get_work_pool() and get_work_pwq() can be used to obtain the pool or pwq
// * corresponding to a work.  Pool is available once the work has been
// * queued anywhere after initialization until it is sync canceled.  pwq is
// * available only while the work item is queued.
// *
// * %WORK_OFFQ_CANCELING is used to mark a work item which is being
// * canceled.  While being canceled, a work item may have its PENDING set
// * but stay off timer and worklist for arbitrarily long and nobody should
// * try to steal the PENDING bit.
// */
//static inline void set_work_data(struct work_struct *work, unsigned long data,
//				 unsigned long flags)
//{
//	WARN_ON_ONCE(!work_pending(work));
//	atomic_long_set(&work->data, data | flags | work_static(work));
//}

//static void set_work_pwq(struct work_struct *work, struct pool_workqueue *pwq,
//			 unsigned long extra_flags)
//{
//	set_work_data(work, (unsigned long)pwq,
//		      WORK_STRUCT_PENDING | WORK_STRUCT_PWQ | extra_flags);
//}

//static void set_work_pool_and_keep_pending(struct work_struct *work,
//					   int pool_id)
//{
//	set_work_data(work, (unsigned long)pool_id << WORK_OFFQ_POOL_SHIFT,
//		      WORK_STRUCT_PENDING);
//}

//static void set_work_pool_and_clear_pending(struct work_struct *work,
//					    int pool_id)
//{
//	/*
//	 * The following wmb is paired with the implied mb in
//	 * test_and_set_bit(PENDING) and ensures all updates to @work made
//	 * here are visible to and precede any updates by the next PENDING
//	 * owner.
//	 */
//	smp_wmb();
//	set_work_data(work, (unsigned long)pool_id << WORK_OFFQ_POOL_SHIFT, 0);
//	/*
//	 * The following mb guarantees that previous clear of a PENDING bit
//	 * will not be reordered with any speculative LOADS or STORES from
//	 * work->current_func, which is executed afterwards.  This possible
//	 * reordering can lead to a missed execution on attempt to queue
//	 * the same @work.  E.g. consider this case:
//	 *
//	 *   CPU#0                         CPU#1
//	 *   ----------------------------  --------------------------------
//	 *
//	 * 1  STORE event_indicated
//	 * 2  queue_work_on() {
//	 * 3    test_and_set_bit(PENDING)
//	 * 4 }                             set_..._and_clear_pending() {
//	 * 5                                 set_work_data() # clear bit
//	 * 6                                 smp_mb()
//	 * 7                               work->current_func() {
//	 * 8				      LOAD event_indicated
//	 *				   }
//	 *
//	 * Without an explicit full barrier speculative LOAD on line 8 can
//	 * be executed before CPU#0 does STORE on line 1.  If that happens,
//	 * CPU#0 observes the PENDING bit is still set and new execution of
//	 * a @work is not queued in a hope, that CPU#1 will eventually
//	 * finish the queued @work.  Meanwhile CPU#1 does not see
//	 * event_indicated is set, because speculative LOAD was executed
//	 * before actual STORE.
//	 */
//	smp_mb();
//}

//static void clear_work_data(struct work_struct *work)
//{
//	smp_wmb();	/* see set_work_pool_and_clear_pending() */
//	set_work_data(work, WORK_STRUCT_NO_POOL, 0);
//}

//static struct pool_workqueue *get_work_pwq(struct work_struct *work)
//{
//	unsigned long data = atomic_long_read(&work->data);

//	if (data & WORK_STRUCT_PWQ)
//		return (void *)(data & WORK_STRUCT_WQ_DATA_MASK);
//	else
//		return NULL;
//}

///**
// * get_work_pool - return the worker_pool a given work was associated with
// * @work: the work item of interest
// *
// * Pools are created and destroyed under wq_pool_mutex, and allows read
// * access under RCU read lock.  As such, this function should be
// * called under wq_pool_mutex or inside of a rcu_read_lock() region.
// *
// * All fields of the returned pool are accessible as long as the above
// * mentioned locking is in effect.  If the returned pool needs to be used
// * beyond the critical section, the caller is responsible for ensuring the
// * returned pool is and stays online.
// *
// * Return: The worker_pool @work was last associated with.  %NULL if none.
// */
//static struct worker_pool *get_work_pool(struct work_struct *work)
//{
//	unsigned long data = atomic_long_read(&work->data);
//	int pool_id;

//	assert_rcu_or_pool_mutex();

//	if (data & WORK_STRUCT_PWQ)
//		return ((struct pool_workqueue *)
//			(data & WORK_STRUCT_WQ_DATA_MASK))->pool;

//	pool_id = data >> WORK_OFFQ_POOL_SHIFT;
//	if (pool_id == WORK_OFFQ_POOL_NONE)
//		return NULL;

//	return idr_find(&worker_pool_idr, pool_id);
//}

///**
// * get_work_pool_id - return the worker pool ID a given work is associated with
// * @work: the work item of interest
// *
// * Return: The worker_pool ID @work was last associated with.
// * %WORK_OFFQ_POOL_NONE if none.
// */
//static int get_work_pool_id(struct work_struct *work)
//{
//	unsigned long data = atomic_long_read(&work->data);

//	if (data & WORK_STRUCT_PWQ)
//		return ((struct pool_workqueue *)
//			(data & WORK_STRUCT_WQ_DATA_MASK))->pool->id;

//	return data >> WORK_OFFQ_POOL_SHIFT;
//}

//static void mark_work_canceling(struct work_struct *work)
//{
//	unsigned long pool_id = get_work_pool_id(work);

//	pool_id <<= WORK_OFFQ_POOL_SHIFT;
//	set_work_data(work, pool_id | WORK_OFFQ_CANCELING, WORK_STRUCT_PENDING);
//}

//static bool work_is_canceling(struct work_struct *work)
//{
//	unsigned long data = atomic_long_read(&work->data);

//	return !(data & WORK_STRUCT_PWQ) && (data & WORK_OFFQ_CANCELING);
//}

///*
// * Policy functions.  These define the policies on how the global worker
// * pools are managed.  Unless noted otherwise, these functions assume that
// * they're being called with pool->lock held.
// */

//static bool __need_more_worker(struct worker_pool *pool)
//{
//	return !atomic_read(&pool->nr_running);
//}

///*
// * Need to wake up a worker?  Called from anything but currently
// * running workers.
// *
// * Note that, because unbound workers never contribute to nr_running, this
// * function will always return %true for unbound pools as long as the
// * worklist isn't empty.
// */
//static bool need_more_worker(struct worker_pool *pool)
//{
//	return !list_empty(&pool->worklist) && __need_more_worker(pool);
//}

///* Can I start working?  Called from busy but !running workers. */
//static bool may_start_working(struct worker_pool *pool)
//{
//	return pool->nr_idle;
//}

///* Do I need to keep working?  Called from currently running workers. */
//static bool keep_working(struct worker_pool *pool)
//{
//	return !list_empty(&pool->worklist) &&
//		atomic_read(&pool->nr_running) <= 1;
//}

///* Do we need a new worker?  Called from manager. */
//static bool need_to_create_worker(struct worker_pool *pool)
//{
//	return need_more_worker(pool) && !may_start_working(pool);
//}

///* Do we have too many workers and should some go away? */
//static bool too_many_workers(struct worker_pool *pool)
//{
//	bool managing = pool->flags & POOL_MANAGER_ACTIVE;
//	int nr_idle = pool->nr_idle + managing; /* manager is considered idle */
//	int nr_busy = pool->nr_workers - nr_idle;

//	return nr_idle > 2 && (nr_idle - 2) * MAX_IDLE_WORKERS_RATIO >= nr_busy;
//}

///*
// * Wake up functions.
// */

///* Return the first idle worker.  Safe with preemption disabled */
//static struct worker *first_idle_worker(struct worker_pool *pool)
//{
//	if (unlikely(list_empty(&pool->idle_list)))
//		return NULL;

//	return list_first_entry(&pool->idle_list, struct worker, entry);
//}

///**
// * wake_up_worker - wake up an idle worker
// * @pool: worker pool to wake worker from
// *
// * Wake up the first idle worker of @pool.
// *
// * CONTEXT:
// * raw_spin_lock_irq(pool->lock).
// */
//static void wake_up_worker(struct worker_pool *pool)
//{
//	struct worker *worker = first_idle_worker(pool);

//	if (likely(worker))
//		wake_up_process(worker->task);
//}

///**
// * wq_worker_running - a worker is running again
// * @task: task waking up
// *
// * This function is called when a worker returns from schedule()
// */
//void wq_worker_running(struct task_struct *task)
//{
//	struct worker *worker = kthread_data(task);

//	if (!worker->sleeping)
//		return;
//	if (!(worker->flags & WORKER_NOT_RUNNING))
//		atomic_inc(&worker->pool->nr_running);
//	worker->sleeping = 0;
//}

///**
// * wq_worker_sleeping - a worker is going to sleep
// * @task: task going to sleep
// *
// * This function is called from schedule() when a busy worker is
// * going to sleep. Preemption needs to be disabled to protect ->sleeping
// * assignment.
// */
//void wq_worker_sleeping(struct task_struct *task)
//{
//	struct worker *next, *worker = kthread_data(task);
//	struct worker_pool *pool;

//	/*
//	 * Rescuers, which may not have all the fields set up like normal
//	 * workers, also reach here, let's not access anything before
//	 * checking NOT_RUNNING.
//	 */
//	if (worker->flags & WORKER_NOT_RUNNING)
//		return;

//	pool = worker->pool;

//	/* Return if preempted before wq_worker_running() was reached */
//	if (worker->sleeping)
//		return;

//	worker->sleeping = 1;
//	raw_spin_lock_irq(&pool->lock);

//	/*
//	 * The counterpart of the following dec_and_test, implied mb,
//	 * worklist not empty test sequence is in insert_work().
//	 * Please read comment there.
//	 *
//	 * NOT_RUNNING is clear.  This means that we're bound to and
//	 * running on the local cpu w/ rq lock held and preemption
//	 * disabled, which in turn means that none else could be
//	 * manipulating idle_list, so dereferencing idle_list without pool
//	 * lock is safe.
//	 */
//	if (atomic_dec_and_test(&pool->nr_running) &&
//	    !list_empty(&pool->worklist)) {
//		next = first_idle_worker(pool);
//		if (next)
//			wake_up_process(next->task);
//	}
//	raw_spin_unlock_irq(&pool->lock);
//}

///**
// * wq_worker_last_func - retrieve worker's last work function
// * @task: Task to retrieve last work function of.
// *
// * Determine the last function a worker executed. This is called from
// * the scheduler to get a worker's last known identity.
// *
// * CONTEXT:
// * raw_spin_lock_irq(rq->lock)
// *
// * This function is called during schedule() when a kworker is going
// * to sleep. It's used by psi to identify aggregation workers during
// * dequeuing, to allow periodic aggregation to shut-off when that
// * worker is the last task in the system or cgroup to go to sleep.
// *
// * As this function doesn't involve any workqueue-related locking, it
// * only returns stable values when called from inside the scheduler's
// * queuing and dequeuing paths, when @task, which must be a kworker,
// * is guaranteed to not be processing any works.
// *
// * Return:
// * The last work function %current executed as a worker, NULL if it
// * hasn't executed any work yet.
// */
//work_func_t wq_worker_last_func(struct task_struct *task)
//{
//	struct worker *worker = kthread_data(task);

//	return worker->last_func;
//}

///**
// * worker_set_flags - set worker flags and adjust nr_running accordingly
// * @worker: self
// * @flags: flags to set
// *
// * Set @flags in @worker->flags and adjust nr_running accordingly.
// *
// * CONTEXT:
// * raw_spin_lock_irq(pool->lock)
// */
//static inline void worker_set_flags(struct worker *worker, unsigned int flags)
//{
//	struct worker_pool *pool = worker->pool;

//	WARN_ON_ONCE(worker->task != current);

//	/* If transitioning into NOT_RUNNING, adjust nr_running. */
//	if ((flags & WORKER_NOT_RUNNING) &&
//	    !(worker->flags & WORKER_NOT_RUNNING)) {
//		atomic_dec(&pool->nr_running);
//	}

//	worker->flags |= flags;
//}

///**
// * worker_clr_flags - clear worker flags and adjust nr_running accordingly
// * @worker: self
// * @flags: flags to clear
// *
// * Clear @flags in @worker->flags and adjust nr_running accordingly.
// *
// * CONTEXT:
// * raw_spin_lock_irq(pool->lock)
// */
//static inline void worker_clr_flags(struct worker *worker, unsigned int flags)
//{
//	struct worker_pool *pool = worker->pool;
//	unsigned int oflags = worker->flags;

//	WARN_ON_ONCE(worker->task != current);

//	worker->flags &= ~flags;

//	/*
//	 * If transitioning out of NOT_RUNNING, increment nr_running.  Note
//	 * that the nested NOT_RUNNING is not a noop.  NOT_RUNNING is mask
//	 * of multiple flags, not a single flag.
//	 */
//	if ((flags & WORKER_NOT_RUNNING) && (oflags & WORKER_NOT_RUNNING))
//		if (!(worker->flags & WORKER_NOT_RUNNING))
//			atomic_inc(&pool->nr_running);
//}

///**
// * find_worker_executing_work - find worker which is executing a work
// * @pool: pool of interest
// * @work: work to find worker for
// *
// * Find a worker which is executing @work on @pool by searching
// * @pool->busy_hash which is keyed by the address of @work.  For a worker
// * to match, its current execution should match the address of @work and
// * its work function.  This is to avoid unwanted dependency between
// * unrelated work executions through a work item being recycled while still
// * being executed.
// *
// * This is a bit tricky.  A work item may be freed once its execution
// * starts and nothing prevents the freed area from being recycled for
// * another work item.  If the same work item address ends up being reused
// * before the original execution finishes, workqueue will identify the
// * recycled work item as currently executing and make it wait until the
// * current execution finishes, introducing an unwanted dependency.
// *
// * This function checks the work item address and work function to avoid
// * false positives.  Note that this isn't complete as one may construct a
// * work function which can introduce dependency onto itself through a
// * recycled work item.  Well, if somebody wants to shoot oneself in the
// * foot that badly, there's only so much we can do, and if such deadlock
// * actually occurs, it should be easy to locate the culprit work function.
// *
// * CONTEXT:
// * raw_spin_lock_irq(pool->lock).
// *
// * Return:
// * Pointer to worker which is executing @work if found, %NULL
// * otherwise.
// */
//static struct worker *find_worker_executing_work(struct worker_pool *pool,
//						 struct work_struct *work)
//{
//	struct worker *worker;

//	hash_for_each_possible(pool->busy_hash, worker, hentry,
//			       (unsigned long)work)
//		if (worker->current_work == work &&
//		    worker->current_func == work->func)
//			return worker;

//	return NULL;
//}

///**
// * move_linked_works - move linked works to a list
// * @work: start of series of works to be scheduled
// * @head: target list to append @work to
// * @nextp: out parameter for nested worklist walking
// *
// * Schedule linked works starting from @work to @head.  Work series to
// * be scheduled starts at @work and includes any consecutive work with
// * WORK_STRUCT_LINKED set in its predecessor.
// *
// * If @nextp is not NULL, it's updated to point to the next work of
// * the last scheduled work.  This allows move_linked_works() to be
// * nested inside outer list_for_each_entry_safe().
// *
// * CONTEXT:
// * raw_spin_lock_irq(pool->lock).
// */
//static void move_linked_works(struct work_struct *work, struct list_head *head,
//			      struct work_struct **nextp)
//{
//	struct work_struct *n;

//	/*
//	 * Linked worklist will always end before the end of the list,
//	 * use NULL for list head.
//	 */
//	list_for_each_entry_safe_from(work, n, NULL, entry) {
//		list_move_tail(&work->entry, head);
//		if (!(*work_data_bits(work) & WORK_STRUCT_LINKED))
//			break;
//	}

//	/*
//	 * If we're already inside safe list traversal and have moved
//	 * multiple works to the scheduled queue, the next position
//	 * needs to be updated.
//	 */
//	if (nextp)
//		*nextp = n;
//}

///**
// * get_pwq - get an extra reference on the specified pool_workqueue
// * @pwq: pool_workqueue to get
// *
// * Obtain an extra reference on @pwq.  The caller should guarantee that
// * @pwq has positive refcnt and be holding the matching pool->lock.
// */
//static void get_pwq(struct pool_workqueue *pwq)
//{
//	lockdep_assert_held(&pwq->pool->lock);
//	WARN_ON_ONCE(pwq->refcnt <= 0);
//	pwq->refcnt++;
//}

///**
// * put_pwq - put a pool_workqueue reference
// * @pwq: pool_workqueue to put
// *
// * Drop a reference of @pwq.  If its refcnt reaches zero, schedule its
// * destruction.  The caller should be holding the matching pool->lock.
// */
//static void put_pwq(struct pool_workqueue *pwq)
//{
//	lockdep_assert_held(&pwq->pool->lock);
//	if (likely(--pwq->refcnt))
//		return;
//	if (WARN_ON_ONCE(!(pwq->wq->flags & WQ_UNBOUND)))
//		return;
//	/*
//	 * @pwq can't be released under pool->lock, bounce to
//	 * pwq_unbound_release_workfn().  This never recurses on the same
//	 * pool->lock as this path is taken only for unbound workqueues and
//	 * the release work item is scheduled on a per-cpu workqueue.  To
//	 * avoid lockdep warning, unbound pool->locks are given lockdep
//	 * subclass of 1 in get_unbound_pool().
//	 */
//	schedule_work(&pwq->unbound_release_work);
//}

///**
// * put_pwq_unlocked - put_pwq() with surrounding pool lock/unlock
// * @pwq: pool_workqueue to put (can be %NULL)
// *
// * put_pwq() with locking.  This function also allows %NULL @pwq.
// */
//static void put_pwq_unlocked(struct pool_workqueue *pwq)
//{
//	if (pwq) {
//		/*
//		 * As both pwqs and pools are RCU protected, the
//		 * following lock operations are safe.
//		 */
//		raw_spin_lock_irq(&pwq->pool->lock);
//		put_pwq(pwq);
//		raw_spin_unlock_irq(&pwq->pool->lock);
//	}
//}

//static void pwq_activate_delayed_work(struct work_struct *work)
//{
//	struct pool_workqueue *pwq = get_work_pwq(work);

//	trace_workqueue_activate_work(work);
//	if (list_empty(&pwq->pool->worklist))
//		pwq->pool->watchdog_ts = jiffies;
//	move_linked_works(work, &pwq->pool->worklist, NULL);
//	__clear_bit(WORK_STRUCT_DELAYED_BIT, work_data_bits(work));
//	pwq->nr_active++;
//}

//static void pwq_activate_first_delayed(struct pool_workqueue *pwq)
//{
//	struct work_struct *work = list_first_entry(&pwq->delayed_works,
//						    struct work_struct, entry);

//	pwq_activate_delayed_work(work);
//}

///**
// * pwq_dec_nr_in_flight - decrement pwq's nr_in_flight
// * @pwq: pwq of interest
// * @color: color of work which left the queue
// *
// * A work either has completed or is removed from pending queue,
// * decrement nr_in_flight of its pwq and handle workqueue flushing.
// *
// * CONTEXT:
// * raw_spin_lock_irq(pool->lock).
// */
//static void pwq_dec_nr_in_flight(struct pool_workqueue *pwq, int color)
//{
//	/* uncolored work items don't participate in flushing or nr_active */
//	if (color == WORK_NO_COLOR)
//		goto out_put;

//	pwq->nr_in_flight[color]--;

//	pwq->nr_active--;
//	if (!list_empty(&pwq->delayed_works)) {
//		/* one down, submit a delayed one */
//		if (pwq->nr_active < pwq->max_active)
//			pwq_activate_first_delayed(pwq);
//	}

//	/* is flush in progress and are we at the flushing tip? */
//	if (likely(pwq->flush_color != color))
//		goto out_put;

//	/* are there still in-flight works? */
//	if (pwq->nr_in_flight[color])
//		goto out_put;

//	/* this pwq is done, clear flush_color */
//	pwq->flush_color = -1;

//	/*
//	 * If this was the last pwq, wake up the first flusher.  It
//	 * will handle the rest.
//	 */
//	if (atomic_dec_and_test(&pwq->wq->nr_pwqs_to_flush))
//		complete(&pwq->wq->first_flusher->done);
//out_put:
//	put_pwq(pwq);
//}

///**
// * try_to_grab_pending - steal work item from worklist and disable irq
// * @work: work item to steal
// * @is_dwork: @work is a delayed_work
// * @flags: place to store irq state
// *
// * Try to grab PENDING bit of @work.  This function can handle @work in any
// * stable state - idle, on timer or on worklist.
// *
// * Return:
// *
// *  ========	================================================================
// *  1		if @work was pending and we successfully stole PENDING
// *  0		if @work was idle and we claimed PENDING
// *  -EAGAIN	if PENDING couldn't be grabbed at the moment, safe to busy-retry
// *  -ENOENT	if someone else is canceling @work, this state may persist
// *		for arbitrarily long
// *  ========	================================================================
// *
// * Note:
// * On >= 0 return, the caller owns @work's PENDING bit.  To avoid getting
// * interrupted while holding PENDING and @work off queue, irq must be
// * disabled on entry.  This, combined with delayed_work->timer being
// * irqsafe, ensures that we return -EAGAIN for finite short period of time.
// *
// * On successful return, >= 0, irq is disabled and the caller is
// * responsible for releasing it using local_irq_restore(*@flags).
// *
// * This function is safe to call from any context including IRQ handler.
// */
//static int try_to_grab_pending(struct work_struct *work, bool is_dwork,
//			       unsigned long *flags)
//{
//	struct worker_pool *pool;
//	struct pool_workqueue *pwq;

//	local_irq_save(*flags);

//	/* try to steal the timer if it exists */
//	if (is_dwork) {
//		struct delayed_work *dwork = to_delayed_work(work);

//		/*
//		 * dwork->timer is irqsafe.  If del_timer() fails, it's
//		 * guaranteed that the timer is not queued anywhere and not
//		 * running on the local CPU.
//		 */
//		if (likely(del_timer(&dwork->timer)))
//			return 1;
//	}

//	/* try to claim PENDING the normal way */
//	if (!test_and_set_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work)))
//		return 0;

//	rcu_read_lock();
//	/*
//	 * The queueing is in progress, or it is already queued. Try to
//	 * steal it from ->worklist without clearing WORK_STRUCT_PENDING.
//	 */
//	pool = get_work_pool(work);
//	if (!pool)
//		goto fail;

//	raw_spin_lock(&pool->lock);
//	/*
//	 * work->data is guaranteed to point to pwq only while the work
//	 * item is queued on pwq->wq, and both updating work->data to point
//	 * to pwq on queueing and to pool on dequeueing are done under
//	 * pwq->pool->lock.  This in turn guarantees that, if work->data
//	 * points to pwq which is associated with a locked pool, the work
//	 * item is currently queued on that pool.
//	 */
//	pwq = get_work_pwq(work);
//	if (pwq && pwq->pool == pool) {
//		debug_work_deactivate(work);

//		/*
//		 * A delayed work item cannot be grabbed directly because
//		 * it might have linked NO_COLOR work items which, if left
//		 * on the delayed_list, will confuse pwq->nr_active
//		 * management later on and cause stall.  Make sure the work
//		 * item is activated before grabbing.
//		 */
//		if (*work_data_bits(work) & WORK_STRUCT_DELAYED)
//			pwq_activate_delayed_work(work);

//		list_del_init(&work->entry);
//		pwq_dec_nr_in_flight(pwq, get_work_color(work));

//		/* work->data points to pwq iff queued, point to pool */
//		set_work_pool_and_keep_pending(work, pool->id);

//		raw_spin_unlock(&pool->lock);
//		rcu_read_unlock();
//		return 1;
//	}
//	raw_spin_unlock(&pool->lock);
//fail:
//	rcu_read_unlock();
//	local_irq_restore(*flags);
//	if (work_is_canceling(work))
//		return -ENOENT;
//	cpu_relax();
//	return -EAGAIN;
//}

///**
// * insert_work - insert a work into a pool
// * @pwq: pwq @work belongs to
// * @work: work to insert
// * @head: insertion point
// * @extra_flags: extra WORK_STRUCT_* flags to set
// *
// * Insert @work which belongs to @pwq after @head.  @extra_flags is or'd to
// * work_struct flags.
// *
// * CONTEXT:
// * raw_spin_lock_irq(pool->lock).
// */
//static void insert_work(struct pool_workqueue *pwq, struct work_struct *work,
//			struct list_head *head, unsigned int extra_flags)
//{
//	struct worker_pool *pool = pwq->pool;

//	/* we own @work, set data and link */
//	set_work_pwq(work, pwq, extra_flags);
//	list_add_tail(&work->entry, head);
//	get_pwq(pwq);

//	/*
//	 * Ensure either wq_worker_sleeping() sees the above
//	 * list_add_tail() or we see zero nr_running to avoid workers lying
//	 * around lazily while there are works to be processed.
//	 */
//	smp_mb();

//	if (__need_more_worker(pool))
//		wake_up_worker(pool);
//}

///*
// * Test whether @work is being queued from another work executing on the
// * same workqueue.
// */
//static bool is_chained_work(struct workqueue_struct *wq)
//{
//	struct worker *worker;

//	worker = current_wq_worker();
//	/*
//	 * Return %true iff I'm a worker executing a work item on @wq.  If
//	 * I'm @worker, it's safe to dereference it without locking.
//	 */
//	return worker && worker->current_pwq->wq == wq;
//}

///*
// * When queueing an unbound work item to a wq, prefer local CPU if allowed
// * by wq_unbound_cpumask.  Otherwise, round robin among the allowed ones to
// * avoid perturbing sensitive tasks.
// */
//static int wq_select_unbound_cpu(int cpu)
//{
//	static bool printed_dbg_warning;
//	int new_cpu;

//	if (likely(!wq_debug_force_rr_cpu)) {
//		if (cpumask_test_cpu(cpu, wq_unbound_cpumask))
//			return cpu;
//	} else if (!printed_dbg_warning) {
//		pr_warn("workqueue: round-robin CPU selection forced, expect performance impact\n");
//		printed_dbg_warning = true;
//	}

//	if (cpumask_empty(wq_unbound_cpumask))
//		return cpu;

//	new_cpu = __this_cpu_read(wq_rr_cpu_last);
//	new_cpu = cpumask_next_and(new_cpu, wq_unbound_cpumask, cpu_online_mask);
//	if (unlikely(new_cpu >= nr_cpu_ids)) {
//		new_cpu = cpumask_first_and(wq_unbound_cpumask, cpu_online_mask);
//		if (unlikely(new_cpu >= nr_cpu_ids))
//			return cpu;
//	}
//	__this_cpu_write(wq_rr_cpu_last, new_cpu);

//	return new_cpu;
//}

//static void __queue_work(int cpu, struct workqueue_struct *wq,
//			 struct work_struct *work)
//{
//	struct pool_workqueue *pwq;
//	struct worker_pool *last_pool;
//	struct list_head *worklist;
//	unsigned int work_flags;
//	unsigned int req_cpu = cpu;

//	/*
//	 * While a work item is PENDING && off queue, a task trying to
//	 * steal the PENDING will busy-loop waiting for it to either get
//	 * queued or lose PENDING.  Grabbing PENDING and queueing should
//	 * happen with IRQ disabled.
//	 */
//	lockdep_assert_irqs_disabled();


//	/* if draining, only works from the same workqueue are allowed */
//	if (unlikely(wq->flags & __WQ_DRAINING) &&
//	    WARN_ON_ONCE(!is_chained_work(wq)))
//		return;
//	rcu_read_lock();
//retry:
//	/* pwq which will be used unless @work is executing elsewhere */
//	if (wq->flags & WQ_UNBOUND) {
//		if (req_cpu == WORK_CPU_UNBOUND)
//			cpu = wq_select_unbound_cpu(raw_smp_processor_id());
//		pwq = unbound_pwq_by_node(wq, cpu_to_node(cpu));
//	} else {
//		if (req_cpu == WORK_CPU_UNBOUND)
//			cpu = raw_smp_processor_id();
//		pwq = per_cpu_ptr(wq->cpu_pwqs, cpu);
//	}

//	/*
//	 * If @work was previously on a different pool, it might still be
//	 * running there, in which case the work needs to be queued on that
//	 * pool to guarantee non-reentrancy.
//	 */
//	last_pool = get_work_pool(work);
//	if (last_pool && last_pool != pwq->pool) {
//		struct worker *worker;

//		raw_spin_lock(&last_pool->lock);

//		worker = find_worker_executing_work(last_pool, work);

//		if (worker && worker->current_pwq->wq == wq) {
//			pwq = worker->current_pwq;
//		} else {
//			/* meh... not running there, queue here */
//			raw_spin_unlock(&last_pool->lock);
//			raw_spin_lock(&pwq->pool->lock);
//		}
//	} else {
//		raw_spin_lock(&pwq->pool->lock);
//	}

//	/*
//	 * pwq is determined and locked.  For unbound pools, we could have
//	 * raced with pwq release and it could already be dead.  If its
//	 * refcnt is zero, repeat pwq selection.  Note that pwqs never die
//	 * without another pwq replacing it in the numa_pwq_tbl or while
//	 * work items are executing on it, so the retrying is guaranteed to
//	 * make forward-progress.
//	 */
//	if (unlikely(!pwq->refcnt)) {
//		if (wq->flags & WQ_UNBOUND) {
//			raw_spin_unlock(&pwq->pool->lock);
//			cpu_relax();
//			goto retry;
//		}
//		/* oops */
//		WARN_ONCE(true, "workqueue: per-cpu pwq for %s on cpu%d has 0 refcnt",
//			  wq->name, cpu);
//	}

//	/* pwq determined, queue */
//	trace_workqueue_queue_work(req_cpu, pwq, work);

//	if (WARN_ON(!list_empty(&work->entry)))
//		goto out;

//	pwq->nr_in_flight[pwq->work_color]++;
//	work_flags = work_color_to_flags(pwq->work_color);

//	if (likely(pwq->nr_active < pwq->max_active)) {
//		trace_workqueue_activate_work(work);
//		pwq->nr_active++;
//		worklist = &pwq->pool->worklist;
//		if (list_empty(worklist))
//			pwq->pool->watchdog_ts = jiffies;
//	} else {
//		work_flags |= WORK_STRUCT_DELAYED;
//		worklist = &pwq->delayed_works;
//	}

//	debug_work_activate(work);
//	insert_work(pwq, work, worklist, work_flags);

//out:
//	raw_spin_unlock(&pwq->pool->lock);
//	rcu_read_unlock();
//}

/**
 * queue_work_on - queue work on specific cpu
 * @cpu: CPU number to execute work on
 * @wq: workqueue to use
 * @work: work to queue
 *
 * We queue the work to a specific CPU, the caller must ensure it
 * can't go away.
 *
 * Return: %false if @work was already on a queue, %true otherwise.
 */
bool queue_work_on(int cpu, struct workqueue_struct *wq,
		   struct work_struct *work)
{
	bool ret = false;
	unsigned long flags;

	local_irq_save(flags);

	if (!test_and_set_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work))) {
//		__queue_work(cpu, wq, work);
		ret = true;
	}

	local_irq_restore(flags);
	return ret;
}
EXPORT_SYMBOL(queue_work_on);

///**
// * workqueue_select_cpu_near - Select a CPU based on NUMA node
// * @node: NUMA node ID that we want to select a CPU from
// *
// * This function will attempt to find a "random" cpu available on a given
// * node. If there are no CPUs available on the given node it will return
// * WORK_CPU_UNBOUND indicating that we should just schedule to any
// * available CPU if we need to schedule this work.
// */
//static int workqueue_select_cpu_near(int node)
//{
//	int cpu;

//	/* No point in doing this if NUMA isn't enabled for workqueues */
//	if (!wq_numa_enabled)
//		return WORK_CPU_UNBOUND;

//	/* Delay binding to CPU if node is not valid or online */
//	if (node < 0 || node >= MAX_NUMNODES || !node_online(node))
//		return WORK_CPU_UNBOUND;

//	/* Use local node/cpu if we are already there */
//	cpu = raw_smp_processor_id();
//	if (node == cpu_to_node(cpu))
//		return cpu;

//	/* Use "random" otherwise know as "first" online CPU of node */
//	cpu = cpumask_any_and(cpumask_of_node(node), cpu_online_mask);

//	/* If CPU is valid return that, otherwise just defer */
//	return cpu < nr_cpu_ids ? cpu : WORK_CPU_UNBOUND;
//}

/**
 * queue_work_node - queue work on a "random" cpu for a given NUMA node
 * @node: NUMA node that we are targeting the work for
 * @wq: workqueue to use
 * @work: work to queue
 *
 * We queue the work to a "random" CPU within a given NUMA node. The basic
 * idea here is to provide a way to somehow associate work with a given
 * NUMA node.
 *
 * This function will only make a best effort attempt at getting this onto
 * the right NUMA node. If no node is requested or the requested node is
 * offline then we just fall back to standard queue_work behavior.
 *
 * Currently the "random" CPU ends up being the first available CPU in the
 * intersection of cpu_online_mask and the cpumask of the node, unless we
 * are running on the node. In that case we just use the current CPU.
 *
 * Return: %false if @work was already on a queue, %true otherwise.
 */
bool queue_work_node(int node, struct workqueue_struct *wq,
		     struct work_struct *work)
{
	unsigned long flags;
	bool ret = false;

	/*
	 * This current implementation is specific to unbound workqueues.
	 * Specifically we only return the first available CPU for a given
	 * node instead of cycling through individual CPUs within the node.
	 *
	 * If this is used with a per-cpu workqueue then the logic in
	 * workqueue_select_cpu_near would need to be updated to allow for
	 * some round robin type logic.
	 */
	WARN_ON_ONCE(!(wq->flags & WQ_UNBOUND));

	local_irq_save(flags);

	if (!test_and_set_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work))) {
//		int cpu = workqueue_select_cpu_near(node);

//		__queue_work(cpu, wq, work);
		ret = true;
	}

	local_irq_restore(flags);
	return ret;
}
EXPORT_SYMBOL_GPL(queue_work_node);

void delayed_work_timer_fn(struct timer_list *t)
{
//	struct delayed_work *dwork = from_timer(dwork, t, timer);

//	/* should have been called from irqsafe timer with irq already off */
//	__queue_work(dwork->cpu, dwork->wq, &dwork->work);
}
EXPORT_SYMBOL(delayed_work_timer_fn);

static void __queue_delayed_work(int cpu, struct workqueue_struct *wq,
				struct delayed_work *dwork, unsigned long delay)
{
	struct timer_list *timer = &dwork->timer;
	struct work_struct *work = &dwork->work;

	WARN_ON_ONCE(!wq);
	WARN_ON_ONCE(timer->function != delayed_work_timer_fn);
	WARN_ON_ONCE(timer_pending(timer));
	WARN_ON_ONCE(!list_empty(&work->entry));

	/*
	 * If @delay is 0, queue @dwork->work immediately.  This is for
	 * both optimization and correctness.  The earliest @timer can
	 * expire is on the closest next tick and delayed_work users depend
	 * on that there's no such delay when @delay is 0.
	 */
	if (!delay) {
//		__queue_work(cpu, wq, &dwork->work);
		return;
	}

	dwork->wq = wq;
	dwork->cpu = cpu;
	timer->expires = jiffies + delay;

	if (unlikely(cpu != WORK_CPU_UNBOUND))
		add_timer_on(timer, cpu);
	else
		add_timer(timer);
}

/**
 * queue_delayed_work_on - queue work on specific CPU after delay
 * @cpu: CPU number to execute work on
 * @wq: workqueue to use
 * @dwork: work to queue
 * @delay: number of jiffies to wait before queueing
 *
 * Return: %false if @work was already on a queue, %true otherwise.  If
 * @delay is zero and @dwork is idle, it will be scheduled for immediate
 * execution.
 */
bool queue_delayed_work_on(int cpu, struct workqueue_struct *wq,
			   struct delayed_work *dwork, unsigned long delay)
{
	struct work_struct *work = &dwork->work;
	bool ret = false;
	unsigned long flags;

	/* read the comment in __queue_work() */
	local_irq_save(flags);

	if (!test_and_set_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work))) {
		__queue_delayed_work(cpu, wq, dwork, delay);
		ret = true;
	}

	local_irq_restore(flags);
	return ret;
}
EXPORT_SYMBOL(queue_delayed_work_on);

///**
// * mod_delayed_work_on - modify delay of or queue a delayed work on specific CPU
// * @cpu: CPU number to execute work on
// * @wq: workqueue to use
// * @dwork: work to queue
// * @delay: number of jiffies to wait before queueing
// *
// * If @dwork is idle, equivalent to queue_delayed_work_on(); otherwise,
// * modify @dwork's timer so that it expires after @delay.  If @delay is
// * zero, @work is guaranteed to be scheduled immediately regardless of its
// * current state.
// *
// * Return: %false if @dwork was idle and queued, %true if @dwork was
// * pending and its timer was modified.
// *
// * This function is safe to call from any context including IRQ handler.
// * See try_to_grab_pending() for details.
// */
//bool mod_delayed_work_on(int cpu, struct workqueue_struct *wq,
//			 struct delayed_work *dwork, unsigned long delay)
//{
//	unsigned long flags;
//	int ret;

//	do {
//		ret = try_to_grab_pending(&dwork->work, true, &flags);
//	} while (unlikely(ret == -EAGAIN));

//	if (likely(ret >= 0)) {
//		__queue_delayed_work(cpu, wq, dwork, delay);
//		local_irq_restore(flags);
//	}

//	/* -ENOENT from try_to_grab_pending() becomes %true */
//	return ret;
//}
//EXPORT_SYMBOL_GPL(mod_delayed_work_on);

//static void rcu_work_rcufn(struct rcu_head *rcu)
//{
//	struct rcu_work *rwork = container_of(rcu, struct rcu_work, rcu);

//	/* read the comment in __queue_work() */
//	local_irq_disable();
//	__queue_work(WORK_CPU_UNBOUND, rwork->wq, &rwork->work);
//	local_irq_enable();
//}

///**
// * queue_rcu_work - queue work after a RCU grace period
// * @wq: workqueue to use
// * @rwork: work to queue
// *
// * Return: %false if @rwork was already pending, %true otherwise.  Note
// * that a full RCU grace period is guaranteed only after a %true return.
// * While @rwork is guaranteed to be executed after a %false return, the
// * execution may happen before a full RCU grace period has passed.
// */
//bool queue_rcu_work(struct workqueue_struct *wq, struct rcu_work *rwork)
//{
//	struct work_struct *work = &rwork->work;

//	if (!test_and_set_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work))) {
//		rwork->wq = wq;
//		call_rcu(&rwork->rcu, rcu_work_rcufn);
//		return true;
//	}

//	return false;
//}
//EXPORT_SYMBOL(queue_rcu_work);

///**
// * worker_enter_idle - enter idle state
// * @worker: worker which is entering idle state
// *
// * @worker is entering idle state.  Update stats and idle timer if
// * necessary.
// *
// * LOCKING:
// * raw_spin_lock_irq(pool->lock).
// */
//static void worker_enter_idle(struct worker *worker)
//{
//	struct worker_pool *pool = worker->pool;

//	if (WARN_ON_ONCE(worker->flags & WORKER_IDLE) ||
//	    WARN_ON_ONCE(!list_empty(&worker->entry) &&
//			 (worker->hentry.next || worker->hentry.pprev)))
//		return;

//	/* can't use worker_set_flags(), also called from create_worker() */
//	worker->flags |= WORKER_IDLE;
//	pool->nr_idle++;
//	worker->last_active = jiffies;

//	/* idle_list is LIFO */
//	list_add(&worker->entry, &pool->idle_list);

//	if (too_many_workers(pool) && !timer_pending(&pool->idle_timer))
//		mod_timer(&pool->idle_timer, jiffies + IDLE_WORKER_TIMEOUT);

//	/*
//	 * Sanity check nr_running.  Because unbind_workers() releases
//	 * pool->lock between setting %WORKER_UNBOUND and zapping
//	 * nr_running, the warning may trigger spuriously.  Check iff
//	 * unbind is not in progress.
//	 */
//	WARN_ON_ONCE(!(pool->flags & POOL_DISASSOCIATED) &&
//		     pool->nr_workers == pool->nr_idle &&
//		     atomic_read(&pool->nr_running));
//}

///**
// * worker_leave_idle - leave idle state
// * @worker: worker which is leaving idle state
// *
// * @worker is leaving idle state.  Update stats.
// *
// * LOCKING:
// * raw_spin_lock_irq(pool->lock).
// */
//static void worker_leave_idle(struct worker *worker)
//{
//	struct worker_pool *pool = worker->pool;

//	if (WARN_ON_ONCE(!(worker->flags & WORKER_IDLE)))
//		return;
//	worker_clr_flags(worker, WORKER_IDLE);
//	pool->nr_idle--;
//	list_del_init(&worker->entry);
//}

//static struct worker *alloc_worker(int node)
//{
//	struct worker *worker;

//	worker = kzalloc_node(sizeof(*worker), GFP_KERNEL, node);
//	if (worker) {
//		INIT_LIST_HEAD(&worker->entry);
//		INIT_LIST_HEAD(&worker->scheduled);
//		INIT_LIST_HEAD(&worker->node);
//		/* on creation a worker is in !idle && prep state */
//		worker->flags = WORKER_PREP;
//	}
//	return worker;
//}

///**
// * worker_attach_to_pool() - attach a worker to a pool
// * @worker: worker to be attached
// * @pool: the target pool
// *
// * Attach @worker to @pool.  Once attached, the %WORKER_UNBOUND flag and
// * cpu-binding of @worker are kept coordinated with the pool across
// * cpu-[un]hotplugs.
// */
//static void worker_attach_to_pool(struct worker *worker,
//				   struct worker_pool *pool)
//{
//	mutex_lock(&wq_pool_attach_mutex);

//	/*
//	 * The wq_pool_attach_mutex ensures %POOL_DISASSOCIATED remains
//	 * stable across this function.  See the comments above the flag
//	 * definition for details.
//	 */
//	if (pool->flags & POOL_DISASSOCIATED)
//		worker->flags |= WORKER_UNBOUND;

//	if (worker->rescue_wq)
//		set_cpus_allowed_ptr(worker->task, pool->attrs->cpumask);

//	list_add_tail(&worker->node, &pool->workers);
//	worker->pool = pool;

//	mutex_unlock(&wq_pool_attach_mutex);
//}

///**
// * worker_detach_from_pool() - detach a worker from its pool
// * @worker: worker which is attached to its pool
// *
// * Undo the attaching which had been done in worker_attach_to_pool().  The
// * caller worker shouldn't access to the pool after detached except it has
// * other reference to the pool.
// */
//static void worker_detach_from_pool(struct worker *worker)
//{
//	struct worker_pool *pool = worker->pool;
//	struct completion *detach_completion = NULL;

//	mutex_lock(&wq_pool_attach_mutex);

//	list_del(&worker->node);
//	worker->pool = NULL;

//	if (list_empty(&pool->workers))
//		detach_completion = pool->detach_completion;
//	mutex_unlock(&wq_pool_attach_mutex);

//	/* clear leftover flags without pool->lock after it is detached */
//	worker->flags &= ~(WORKER_UNBOUND | WORKER_REBOUND);

//	if (detach_completion)
//		complete(detach_completion);
//}

///**
// * create_worker - create a new workqueue worker
// * @pool: pool the new worker will belong to
// *
// * Create and start a new worker which is attached to @pool.
// *
// * CONTEXT:
// * Might sleep.  Does GFP_KERNEL allocations.
// *
// * Return:
// * Pointer to the newly created worker.
// */
//static struct worker *create_worker(struct worker_pool *pool)
//{
//	struct worker *worker = NULL;
//	int id = -1;
//	char id_buf[16];

//	/* ID is needed to determine kthread name */
//	id = ida_simple_get(&pool->worker_ida, 0, 0, GFP_KERNEL);
//	if (id < 0)
//		goto fail;

//	worker = alloc_worker(pool->node);
//	if (!worker)
//		goto fail;

//	worker->id = id;

//	if (pool->cpu >= 0)
//		snprintf(id_buf, sizeof(id_buf), "%d:%d%s", pool->cpu, id,
//			 pool->attrs->nice < 0  ? "H" : "");
//	else
//		snprintf(id_buf, sizeof(id_buf), "u%d:%d", pool->id, id);

//	worker->task = kthread_create_on_node(worker_thread, worker, pool->node,
//					      "kworker/%s", id_buf);
//	if (IS_ERR(worker->task))
//		goto fail;

//	set_user_nice(worker->task, pool->attrs->nice);
//	kthread_bind_mask(worker->task, pool->attrs->cpumask);

//	/* successful, attach the worker to the pool */
//	worker_attach_to_pool(worker, pool);

//	/* start the newly created worker */
//	raw_spin_lock_irq(&pool->lock);
//	worker->pool->nr_workers++;
//	worker_enter_idle(worker);
//	wake_up_process(worker->task);
//	raw_spin_unlock_irq(&pool->lock);

//	return worker;

//fail:
//	if (id >= 0)
//		ida_simple_remove(&pool->worker_ida, id);
//	kfree(worker);
//	return NULL;
//}

///**
// * destroy_worker - destroy a workqueue worker
// * @worker: worker to be destroyed
// *
// * Destroy @worker and adjust @pool stats accordingly.  The worker should
// * be idle.
// *
// * CONTEXT:
// * raw_spin_lock_irq(pool->lock).
// */
//static void destroy_worker(struct worker *worker)
//{
//	struct worker_pool *pool = worker->pool;

//	lockdep_assert_held(&pool->lock);

//	/* sanity check frenzy */
//	if (WARN_ON(worker->current_work) ||
//	    WARN_ON(!list_empty(&worker->scheduled)) ||
//	    WARN_ON(!(worker->flags & WORKER_IDLE)))
//		return;

//	pool->nr_workers--;
//	pool->nr_idle--;

//	list_del_init(&worker->entry);
//	worker->flags |= WORKER_DIE;
//	wake_up_process(worker->task);
//}

//static void idle_worker_timeout(struct timer_list *t)
//{
//	struct worker_pool *pool = from_timer(pool, t, idle_timer);

//	raw_spin_lock_irq(&pool->lock);

//	while (too_many_workers(pool)) {
//		struct worker *worker;
//		unsigned long expires;

//		/* idle_list is kept in LIFO order, check the last one */
//		worker = list_entry(pool->idle_list.prev, struct worker, entry);
//		expires = worker->last_active + IDLE_WORKER_TIMEOUT;

//		if (time_before(jiffies, expires)) {
//			mod_timer(&pool->idle_timer, expires);
//			break;
//		}

//		destroy_worker(worker);
//	}

//	raw_spin_unlock_irq(&pool->lock);
//}

//static void send_mayday(struct work_struct *work)
//{
//	struct pool_workqueue *pwq = get_work_pwq(work);
//	struct workqueue_struct *wq = pwq->wq;

//	lockdep_assert_held(&wq_mayday_lock);

//	if (!wq->rescuer)
//		return;

//	/* mayday mayday mayday */
//	if (list_empty(&pwq->mayday_node)) {
//		/*
//		 * If @pwq is for an unbound wq, its base ref may be put at
//		 * any time due to an attribute change.  Pin @pwq until the
//		 * rescuer is done with it.
//		 */
//		get_pwq(pwq);
//		list_add_tail(&pwq->mayday_node, &wq->maydays);
//		wake_up_process(wq->rescuer->task);
//	}
//}

//static void pool_mayday_timeout(struct timer_list *t)
//{
//	struct worker_pool *pool = from_timer(pool, t, mayday_timer);
//	struct work_struct *work;

//	raw_spin_lock_irq(&pool->lock);
//	raw_spin_lock(&wq_mayday_lock);		/* for wq->maydays */

//	if (need_to_create_worker(pool)) {
//		/*
//		 * We've been trying to create a new worker but
//		 * haven't been successful.  We might be hitting an
//		 * allocation deadlock.  Send distress signals to
//		 * rescuers.
//		 */
//		list_for_each_entry(work, &pool->worklist, entry)
//			send_mayday(work);
//	}

//	raw_spin_unlock(&wq_mayday_lock);
//	raw_spin_unlock_irq(&pool->lock);

//	mod_timer(&pool->mayday_timer, jiffies + MAYDAY_INTERVAL);
//}

///**
// * maybe_create_worker - create a new worker if necessary
// * @pool: pool to create a new worker for
// *
// * Create a new worker for @pool if necessary.  @pool is guaranteed to
// * have at least one idle worker on return from this function.  If
// * creating a new worker takes longer than MAYDAY_INTERVAL, mayday is
// * sent to all rescuers with works scheduled on @pool to resolve
// * possible allocation deadlock.
// *
// * On return, need_to_create_worker() is guaranteed to be %false and
// * may_start_working() %true.
// *
// * LOCKING:
// * raw_spin_lock_irq(pool->lock) which may be released and regrabbed
// * multiple times.  Does GFP_KERNEL allocations.  Called only from
// * manager.
// */
//static void maybe_create_worker(struct worker_pool *pool)
//__releases(&pool->lock)
//__acquires(&pool->lock)
//{
//restart:
//	raw_spin_unlock_irq(&pool->lock);

//	/* if we don't make progress in MAYDAY_INITIAL_TIMEOUT, call for help */
//	mod_timer(&pool->mayday_timer, jiffies + MAYDAY_INITIAL_TIMEOUT);

//	while (true) {
//		if (create_worker(pool) || !need_to_create_worker(pool))
//			break;

//		schedule_timeout_interruptible(CREATE_COOLDOWN);

//		if (!need_to_create_worker(pool))
//			break;
//	}

//	del_timer_sync(&pool->mayday_timer);
//	raw_spin_lock_irq(&pool->lock);
//	/*
//	 * This is necessary even after a new worker was just successfully
//	 * created as @pool->lock was dropped and the new worker might have
//	 * already become busy.
//	 */
//	if (need_to_create_worker(pool))
//		goto restart;
//}

///**
// * manage_workers - manage worker pool
// * @worker: self
// *
// * Assume the manager role and manage the worker pool @worker belongs
// * to.  At any given time, there can be only zero or one manager per
// * pool.  The exclusion is handled automatically by this function.
// *
// * The caller can safely start processing works on false return.  On
// * true return, it's guaranteed that need_to_create_worker() is false
// * and may_start_working() is true.
// *
// * CONTEXT:
// * raw_spin_lock_irq(pool->lock) which may be released and regrabbed
// * multiple times.  Does GFP_KERNEL allocations.
// *
// * Return:
// * %false if the pool doesn't need management and the caller can safely
// * start processing works, %true if management function was performed and
// * the conditions that the caller verified before calling the function may
// * no longer be true.
// */
//static bool manage_workers(struct worker *worker)
//{
//	struct worker_pool *pool = worker->pool;

//	if (pool->flags & POOL_MANAGER_ACTIVE)
//		return false;

//	pool->flags |= POOL_MANAGER_ACTIVE;
//	pool->manager = worker;

//	maybe_create_worker(pool);

//	pool->manager = NULL;
//	pool->flags &= ~POOL_MANAGER_ACTIVE;
//	rcuwait_wake_up(&manager_wait);
//	return true;
//}

///**
// * process_one_work - process single work
// * @worker: self
// * @work: work to process
// *
// * Process @work.  This function contains all the logics necessary to
// * process a single work including synchronization against and
// * interaction with other workers on the same cpu, queueing and
// * flushing.  As long as context requirement is met, any worker can
// * call this function to process a work.
// *
// * CONTEXT:
// * raw_spin_lock_irq(pool->lock) which is released and regrabbed.
// */
//static void process_one_work(struct worker *worker, struct work_struct *work)
//__releases(&pool->lock)
//__acquires(&pool->lock)
//{
//	struct pool_workqueue *pwq = get_work_pwq(work);
//	struct worker_pool *pool = worker->pool;
//	bool cpu_intensive = pwq->wq->flags & WQ_CPU_INTENSIVE;
//	int work_color;
//	struct worker *collision;
//#ifdef CONFIG_LOCKDEP
//	/*
//	 * It is permissible to free the struct work_struct from
//	 * inside the function that is called from it, this we need to
//	 * take into account for lockdep too.  To avoid bogus "held
//	 * lock freed" warnings as well as problems when looking into
//	 * work->lockdep_map, make a copy and use that here.
//	 */
//	struct lockdep_map lockdep_map;

//	lockdep_copy_map(&lockdep_map, &work->lockdep_map);
//#endif
//	/* ensure we're on the correct CPU */
//	WARN_ON_ONCE(!(pool->flags & POOL_DISASSOCIATED) &&
//		     raw_smp_processor_id() != pool->cpu);

//	/*
//	 * A single work shouldn't be executed concurrently by
//	 * multiple workers on a single cpu.  Check whether anyone is
//	 * already processing the work.  If so, defer the work to the
//	 * currently executing one.
//	 */
//	collision = find_worker_executing_work(pool, work);
//	if (unlikely(collision)) {
//		move_linked_works(work, &collision->scheduled, NULL);
//		return;
//	}

//	/* claim and dequeue */
//	debug_work_deactivate(work);
//	hash_add(pool->busy_hash, &worker->hentry, (unsigned long)work);
//	worker->current_work = work;
//	worker->current_func = work->func;
//	worker->current_pwq = pwq;
//	work_color = get_work_color(work);

//	/*
//	 * Record wq name for cmdline and debug reporting, may get
//	 * overridden through set_worker_desc().
//	 */
//	strscpy(worker->desc, pwq->wq->name, WORKER_DESC_LEN);

//	list_del_init(&work->entry);

//	/*
//	 * CPU intensive works don't participate in concurrency management.
//	 * They're the scheduler's responsibility.  This takes @worker out
//	 * of concurrency management and the next code block will chain
//	 * execution of the pending work items.
//	 */
//	if (unlikely(cpu_intensive))
//		worker_set_flags(worker, WORKER_CPU_INTENSIVE);

//	/*
//	 * Wake up another worker if necessary.  The condition is always
//	 * false for normal per-cpu workers since nr_running would always
//	 * be >= 1 at this point.  This is used to chain execution of the
//	 * pending work items for WORKER_NOT_RUNNING workers such as the
//	 * UNBOUND and CPU_INTENSIVE ones.
//	 */
//	if (need_more_worker(pool))
//		wake_up_worker(pool);

//	/*
//	 * Record the last pool and clear PENDING which should be the last
//	 * update to @work.  Also, do this inside @pool->lock so that
//	 * PENDING and queued state changes happen together while IRQ is
//	 * disabled.
//	 */
//	set_work_pool_and_clear_pending(work, pool->id);

//	raw_spin_unlock_irq(&pool->lock);

//	lock_map_acquire(&pwq->wq->lockdep_map);
//	lock_map_acquire(&lockdep_map);
//	/*
//	 * Strictly speaking we should mark the invariant state without holding
//	 * any locks, that is, before these two lock_map_acquire()'s.
//	 *
//	 * However, that would result in:
//	 *
//	 *   A(W1)
//	 *   WFC(C)
//	 *		A(W1)
//	 *		C(C)
//	 *
//	 * Which would create W1->C->W1 dependencies, even though there is no
//	 * actual deadlock possible. There are two solutions, using a
//	 * read-recursive acquire on the work(queue) 'locks', but this will then
//	 * hit the lockdep limitation on recursive locks, or simply discard
//	 * these locks.
//	 *
//	 * AFAICT there is no possible deadlock scenario between the
//	 * flush_work() and complete() primitives (except for single-threaded
//	 * workqueues), so hiding them isn't a problem.
//	 */
//	lockdep_invariant_state(true);
//	trace_workqueue_execute_start(work);
//	worker->current_func(work);
//	/*
//	 * While we must be careful to not use "work" after this, the trace
//	 * point will only record its address.
//	 */
//	trace_workqueue_execute_end(work, worker->current_func);
//	lock_map_release(&lockdep_map);
//	lock_map_release(&pwq->wq->lockdep_map);

//	if (unlikely(in_atomic() || lockdep_depth(current) > 0)) {
//		pr_err("BUG: workqueue leaked lock or atomic: %s/0x%08x/%d\n"
//		       "     last function: %ps\n",
//		       current->comm, preempt_count(), task_pid_nr(current),
//		       worker->current_func);
//		debug_show_held_locks(current);
//		dump_stack();
//	}

//	/*
//	 * The following prevents a kworker from hogging CPU on !PREEMPTION
//	 * kernels, where a requeueing work item waiting for something to
//	 * happen could deadlock with stop_machine as such work item could
//	 * indefinitely requeue itself while all other CPUs are trapped in
//	 * stop_machine. At the same time, report a quiescent RCU state so
//	 * the same condition doesn't freeze RCU.
//	 */
//	cond_resched();

//	raw_spin_lock_irq(&pool->lock);

//	/* clear cpu intensive status */
//	if (unlikely(cpu_intensive))
//		worker_clr_flags(worker, WORKER_CPU_INTENSIVE);

//	/* tag the worker for identification in schedule() */
//	worker->last_func = worker->current_func;

//	/* we're done with it, release */
//	hash_del(&worker->hentry);
//	worker->current_work = NULL;
//	worker->current_func = NULL;
//	worker->current_pwq = NULL;
//	pwq_dec_nr_in_flight(pwq, work_color);
//}

///**
// * process_scheduled_works - process scheduled works
// * @worker: self
// *
// * Process all scheduled works.  Please note that the scheduled list
// * may change while processing a work, so this function repeatedly
// * fetches a work from the top and executes it.
// *
// * CONTEXT:
// * raw_spin_lock_irq(pool->lock) which may be released and regrabbed
// * multiple times.
// */
//static void process_scheduled_works(struct worker *worker)
//{
//	while (!list_empty(&worker->scheduled)) {
//		struct work_struct *work = list_first_entry(&worker->scheduled,
//						struct work_struct, entry);
//		process_one_work(worker, work);
//	}
//}

//static void set_pf_worker(bool val)
//{
//	mutex_lock(&wq_pool_attach_mutex);
//	if (val)
//		current->flags |= PF_WQ_WORKER;
//	else
//		current->flags &= ~PF_WQ_WORKER;
//	mutex_unlock(&wq_pool_attach_mutex);
//}

///**
// * worker_thread - the worker thread function
// * @__worker: self
// *
// * The worker thread function.  All workers belong to a worker_pool -
// * either a per-cpu one or dynamic unbound one.  These workers process all
// * work items regardless of their specific target workqueue.  The only
// * exception is work items which belong to workqueues with a rescuer which
// * will be explained in rescuer_thread().
// *
// * Return: 0
// */
//static int worker_thread(void *__worker)
//{
//	struct worker *worker = __worker;
//	struct worker_pool *pool = worker->pool;

//	/* tell the scheduler that this is a workqueue worker */
//	set_pf_worker(true);
//woke_up:
//	raw_spin_lock_irq(&pool->lock);

//	/* am I supposed to die? */
//	if (unlikely(worker->flags & WORKER_DIE)) {
//		raw_spin_unlock_irq(&pool->lock);
//		WARN_ON_ONCE(!list_empty(&worker->entry));
//		set_pf_worker(false);

//		set_task_comm(worker->task, "kworker/dying");
//		ida_simple_remove(&pool->worker_ida, worker->id);
//		worker_detach_from_pool(worker);
//		kfree(worker);
//		return 0;
//	}

//	worker_leave_idle(worker);
//recheck:
//	/* no more worker necessary? */
//	if (!need_more_worker(pool))
//		goto sleep;

//	/* do we need to manage? */
//	if (unlikely(!may_start_working(pool)) && manage_workers(worker))
//		goto recheck;

//	/*
//	 * ->scheduled list can only be filled while a worker is
//	 * preparing to process a work or actually processing it.
//	 * Make sure nobody diddled with it while I was sleeping.
//	 */
//	WARN_ON_ONCE(!list_empty(&worker->scheduled));

//	/*
//	 * Finish PREP stage.  We're guaranteed to have at least one idle
//	 * worker or that someone else has already assumed the manager
//	 * role.  This is where @worker starts participating in concurrency
//	 * management if applicable and concurrency management is restored
//	 * after being rebound.  See rebind_workers() for details.
//	 */
//	worker_clr_flags(worker, WORKER_PREP | WORKER_REBOUND);

//	do {
//		struct work_struct *work =
//			list_first_entry(&pool->worklist,
//					 struct work_struct, entry);

//		pool->watchdog_ts = jiffies;

//		if (likely(!(*work_data_bits(work) & WORK_STRUCT_LINKED))) {
//			/* optimization path, not strictly necessary */
//			process_one_work(worker, work);
//			if (unlikely(!list_empty(&worker->scheduled)))
//				process_scheduled_works(worker);
//		} else {
//			move_linked_works(work, &worker->scheduled, NULL);
//			process_scheduled_works(worker);
//		}
//	} while (keep_working(pool));

//	worker_set_flags(worker, WORKER_PREP);
//sleep:
//	/*
//	 * pool->lock is held and there's no work to process and no need to
//	 * manage, sleep.  Workers are woken up only while holding
//	 * pool->lock or from local cpu, so setting the current state
//	 * before releasing pool->lock is enough to prevent losing any
//	 * event.
//	 */
//	worker_enter_idle(worker);
//	__set_current_state(TASK_IDLE);
//	raw_spin_unlock_irq(&pool->lock);
//	schedule();
//	goto woke_up;
//}

///**
// * rescuer_thread - the rescuer thread function
// * @__rescuer: self
// *
// * Workqueue rescuer thread function.  There's one rescuer for each
// * workqueue which has WQ_MEM_RECLAIM set.
// *
// * Regular work processing on a pool may block trying to create a new
// * worker which uses GFP_KERNEL allocation which has slight chance of
// * developing into deadlock if some works currently on the same queue
// * need to be processed to satisfy the GFP_KERNEL allocation.  This is
// * the problem rescuer solves.
// *
// * When such condition is possible, the pool summons rescuers of all
// * workqueues which have works queued on the pool and let them process
// * those works so that forward progress can be guaranteed.
// *
// * This should happen rarely.
// *
// * Return: 0
// */
//static int rescuer_thread(void *__rescuer)
//{
//	struct worker *rescuer = __rescuer;
//	struct workqueue_struct *wq = rescuer->rescue_wq;
//	struct list_head *scheduled = &rescuer->scheduled;
//	bool should_stop;

//	set_user_nice(current, RESCUER_NICE_LEVEL);

//	/*
//	 * Mark rescuer as worker too.  As WORKER_PREP is never cleared, it
//	 * doesn't participate in concurrency management.
//	 */
//	set_pf_worker(true);
//repeat:
//	set_current_state(TASK_IDLE);

//	/*
//	 * By the time the rescuer is requested to stop, the workqueue
//	 * shouldn't have any work pending, but @wq->maydays may still have
//	 * pwq(s) queued.  This can happen by non-rescuer workers consuming
//	 * all the work items before the rescuer got to them.  Go through
//	 * @wq->maydays processing before acting on should_stop so that the
//	 * list is always empty on exit.
//	 */
//	should_stop = kthread_should_stop();

//	/* see whether any pwq is asking for help */
//	raw_spin_lock_irq(&wq_mayday_lock);

//	while (!list_empty(&wq->maydays)) {
//		struct pool_workqueue *pwq = list_first_entry(&wq->maydays,
//					struct pool_workqueue, mayday_node);
//		struct worker_pool *pool = pwq->pool;
//		struct work_struct *work, *n;
//		bool first = true;

//		__set_current_state(TASK_RUNNING);
//		list_del_init(&pwq->mayday_node);

//		raw_spin_unlock_irq(&wq_mayday_lock);

//		worker_attach_to_pool(rescuer, pool);

//		raw_spin_lock_irq(&pool->lock);

//		/*
//		 * Slurp in all works issued via this workqueue and
//		 * process'em.
//		 */
//		WARN_ON_ONCE(!list_empty(scheduled));
//		list_for_each_entry_safe(work, n, &pool->worklist, entry) {
//			if (get_work_pwq(work) == pwq) {
//				if (first)
//					pool->watchdog_ts = jiffies;
//				move_linked_works(work, scheduled, &n);
//			}
//			first = false;
//		}

//		if (!list_empty(scheduled)) {
//			process_scheduled_works(rescuer);

//			/*
//			 * The above execution of rescued work items could
//			 * have created more to rescue through
//			 * pwq_activate_first_delayed() or chained
//			 * queueing.  Let's put @pwq back on mayday list so
//			 * that such back-to-back work items, which may be
//			 * being used to relieve memory pressure, don't
//			 * incur MAYDAY_INTERVAL delay inbetween.
//			 */
//			if (pwq->nr_active && need_to_create_worker(pool)) {
//				raw_spin_lock(&wq_mayday_lock);
//				/*
//				 * Queue iff we aren't racing destruction
//				 * and somebody else hasn't queued it already.
//				 */
//				if (wq->rescuer && list_empty(&pwq->mayday_node)) {
//					get_pwq(pwq);
//					list_add_tail(&pwq->mayday_node, &wq->maydays);
//				}
//				raw_spin_unlock(&wq_mayday_lock);
//			}
//		}

//		/*
//		 * Put the reference grabbed by send_mayday().  @pool won't
//		 * go away while we're still attached to it.
//		 */
//		put_pwq(pwq);

//		/*
//		 * Leave this pool.  If need_more_worker() is %true, notify a
//		 * regular worker; otherwise, we end up with 0 concurrency
//		 * and stalling the execution.
//		 */
//		if (need_more_worker(pool))
//			wake_up_worker(pool);

//		raw_spin_unlock_irq(&pool->lock);

//		worker_detach_from_pool(rescuer);

//		raw_spin_lock_irq(&wq_mayday_lock);
//	}

//	raw_spin_unlock_irq(&wq_mayday_lock);

//	if (should_stop) {
//		__set_current_state(TASK_RUNNING);
//		set_pf_worker(false);
//		return 0;
//	}

//	/* rescuers should never participate in concurrency management */
//	WARN_ON_ONCE(!(rescuer->flags & WORKER_NOT_RUNNING));
//	schedule();
//	goto repeat;
//}

///**
// * check_flush_dependency - check for flush dependency sanity
// * @target_wq: workqueue being flushed
// * @target_work: work item being flushed (NULL for workqueue flushes)
// *
// * %current is trying to flush the whole @target_wq or @target_work on it.
// * If @target_wq doesn't have %WQ_MEM_RECLAIM, verify that %current is not
// * reclaiming memory or running on a workqueue which doesn't have
// * %WQ_MEM_RECLAIM as that can break forward-progress guarantee leading to
// * a deadlock.
// */
//static void check_flush_dependency(struct workqueue_struct *target_wq,
//				   struct work_struct *target_work)
//{
//	work_func_t target_func = target_work ? target_work->func : NULL;
//	struct worker *worker;

//	if (target_wq->flags & WQ_MEM_RECLAIM)
//		return;

//	worker = current_wq_worker();

//	WARN_ONCE(current->flags & PF_MEMALLOC,
//		  "workqueue: PF_MEMALLOC task %d(%s) is flushing !WQ_MEM_RECLAIM %s:%ps",
//		  current->pid, current->comm, target_wq->name, target_func);
//	WARN_ONCE(worker && ((worker->current_pwq->wq->flags &
//			      (WQ_MEM_RECLAIM | __WQ_LEGACY)) == WQ_MEM_RECLAIM),
//		  "workqueue: WQ_MEM_RECLAIM %s:%ps is flushing !WQ_MEM_RECLAIM %s:%ps",
//		  worker->current_pwq->wq->name, worker->current_func,
//		  target_wq->name, target_func);
//}

//struct wq_barrier {
//	struct work_struct	work;
//	struct completion	done;
//	struct task_struct	*task;	/* purely informational */
//};

//static void wq_barrier_func(struct work_struct *work)
//{
//	struct wq_barrier *barr = container_of(work, struct wq_barrier, work);
//	complete(&barr->done);
//}

///**
// * insert_wq_barrier - insert a barrier work
// * @pwq: pwq to insert barrier into
// * @barr: wq_barrier to insert
// * @target: target work to attach @barr to
// * @worker: worker currently executing @target, NULL if @target is not executing
// *
// * @barr is linked to @target such that @barr is completed only after
// * @target finishes execution.  Please note that the ordering
// * guarantee is observed only with respect to @target and on the local
// * cpu.
// *
// * Currently, a queued barrier can't be canceled.  This is because
// * try_to_grab_pending() can't determine whether the work to be
// * grabbed is at the head of the queue and thus can't clear LINKED
// * flag of the previous work while there must be a valid next work
// * after a work with LINKED flag set.
// *
// * Note that when @worker is non-NULL, @target may be modified
// * underneath us, so we can't reliably determine pwq from @target.
// *
// * CONTEXT:
// * raw_spin_lock_irq(pool->lock).
// */
//static void insert_wq_barrier(struct pool_workqueue *pwq,
//			      struct wq_barrier *barr,
//			      struct work_struct *target, struct worker *worker)
//{
//	struct list_head *head;
//	unsigned int linked = 0;

//	/*
//	 * debugobject calls are safe here even with pool->lock locked
//	 * as we know for sure that this will not trigger any of the
//	 * checks and call back into the fixup functions where we
//	 * might deadlock.
//	 */
//	INIT_WORK_ONSTACK(&barr->work, wq_barrier_func);
//	__set_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(&barr->work));

//	init_completion_map(&barr->done, &target->lockdep_map);

//	barr->task = current;

//	/*
//	 * If @target is currently being executed, schedule the
//	 * barrier to the worker; otherwise, put it after @target.
//	 */
//	if (worker)
//		head = worker->scheduled.next;
//	else {
//		unsigned long *bits = work_data_bits(target);

//		head = target->entry.next;
//		/* there can already be other linked works, inherit and set */
//		linked = *bits & WORK_STRUCT_LINKED;
//		__set_bit(WORK_STRUCT_LINKED_BIT, bits);
//	}

//	debug_work_activate(&barr->work);
//	insert_work(pwq, &barr->work, head,
//		    work_color_to_flags(WORK_NO_COLOR) | linked);
//}

///**
// * flush_workqueue_prep_pwqs - prepare pwqs for workqueue flushing
// * @wq: workqueue being flushed
// * @flush_color: new flush color, < 0 for no-op
// * @work_color: new work color, < 0 for no-op
// *
// * Prepare pwqs for workqueue flushing.
// *
// * If @flush_color is non-negative, flush_color on all pwqs should be
// * -1.  If no pwq has in-flight commands at the specified color, all
// * pwq->flush_color's stay at -1 and %false is returned.  If any pwq
// * has in flight commands, its pwq->flush_color is set to
// * @flush_color, @wq->nr_pwqs_to_flush is updated accordingly, pwq
// * wakeup logic is armed and %true is returned.
// *
// * The caller should have initialized @wq->first_flusher prior to
// * calling this function with non-negative @flush_color.  If
// * @flush_color is negative, no flush color update is done and %false
// * is returned.
// *
// * If @work_color is non-negative, all pwqs should have the same
// * work_color which is previous to @work_color and all will be
// * advanced to @work_color.
// *
// * CONTEXT:
// * mutex_lock(wq->mutex).
// *
// * Return:
// * %true if @flush_color >= 0 and there's something to flush.  %false
// * otherwise.
// */
//static bool flush_workqueue_prep_pwqs(struct workqueue_struct *wq,
//				      int flush_color, int work_color)
//{
//	bool wait = false;
//	struct pool_workqueue *pwq;

//	if (flush_color >= 0) {
//		WARN_ON_ONCE(atomic_read(&wq->nr_pwqs_to_flush));
//		atomic_set(&wq->nr_pwqs_to_flush, 1);
//	}

//	for_each_pwq(pwq, wq) {
//		struct worker_pool *pool = pwq->pool;

//		raw_spin_lock_irq(&pool->lock);

//		if (flush_color >= 0) {
//			WARN_ON_ONCE(pwq->flush_color != -1);

//			if (pwq->nr_in_flight[flush_color]) {
//				pwq->flush_color = flush_color;
//				atomic_inc(&wq->nr_pwqs_to_flush);
//				wait = true;
//			}
//		}

//		if (work_color >= 0) {
//			WARN_ON_ONCE(work_color != work_next_color(pwq->work_color));
//			pwq->work_color = work_color;
//		}

//		raw_spin_unlock_irq(&pool->lock);
//	}

//	if (flush_color >= 0 && atomic_dec_and_test(&wq->nr_pwqs_to_flush))
//		complete(&wq->first_flusher->done);

//	return wait;
//}

///**
// * flush_workqueue - ensure that any scheduled work has run to completion.
// * @wq: workqueue to flush
// *
// * This function sleeps until all work items which were queued on entry
// * have finished execution, but it is not livelocked by new incoming ones.
// */
//void flush_workqueue(struct workqueue_struct *wq)
//{
//	struct wq_flusher this_flusher = {
//		.list = LIST_HEAD_INIT(this_flusher.list),
//		.flush_color = -1,
//		.done = COMPLETION_INITIALIZER_ONSTACK_MAP(this_flusher.done, wq->lockdep_map),
//	};
//	int next_color;

//	if (WARN_ON(!wq_online))
//		return;

//	lock_map_acquire(&wq->lockdep_map);
//	lock_map_release(&wq->lockdep_map);

//	mutex_lock(&wq->mutex);

//	/*
//	 * Start-to-wait phase
//	 */
//	next_color = work_next_color(wq->work_color);

//	if (next_color != wq->flush_color) {
//		/*
//		 * Color space is not full.  The current work_color
//		 * becomes our flush_color and work_color is advanced
//		 * by one.
//		 */
//		WARN_ON_ONCE(!list_empty(&wq->flusher_overflow));
//		this_flusher.flush_color = wq->work_color;
//		wq->work_color = next_color;

//		if (!wq->first_flusher) {
//			/* no flush in progress, become the first flusher */
//			WARN_ON_ONCE(wq->flush_color != this_flusher.flush_color);

//			wq->first_flusher = &this_flusher;

//			if (!flush_workqueue_prep_pwqs(wq, wq->flush_color,
//						       wq->work_color)) {
//				/* nothing to flush, done */
//				wq->flush_color = next_color;
//				wq->first_flusher = NULL;
//				goto out_unlock;
//			}
//		} else {
//			/* wait in queue */
//			WARN_ON_ONCE(wq->flush_color == this_flusher.flush_color);
//			list_add_tail(&this_flusher.list, &wq->flusher_queue);
//			flush_workqueue_prep_pwqs(wq, -1, wq->work_color);
//		}
//	} else {
//		/*
//		 * Oops, color space is full, wait on overflow queue.
//		 * The next flush completion will assign us
//		 * flush_color and transfer to flusher_queue.
//		 */
//		list_add_tail(&this_flusher.list, &wq->flusher_overflow);
//	}

//	check_flush_dependency(wq, NULL);

//	mutex_unlock(&wq->mutex);

//	wait_for_completion(&this_flusher.done);

//	/*
//	 * Wake-up-and-cascade phase
//	 *
//	 * First flushers are responsible for cascading flushes and
//	 * handling overflow.  Non-first flushers can simply return.
//	 */
//	if (READ_ONCE(wq->first_flusher) != &this_flusher)
//		return;

//	mutex_lock(&wq->mutex);

//	/* we might have raced, check again with mutex held */
//	if (wq->first_flusher != &this_flusher)
//		goto out_unlock;

//	WRITE_ONCE(wq->first_flusher, NULL);

//	WARN_ON_ONCE(!list_empty(&this_flusher.list));
//	WARN_ON_ONCE(wq->flush_color != this_flusher.flush_color);

//	while (true) {
//		struct wq_flusher *next, *tmp;

//		/* complete all the flushers sharing the current flush color */
//		list_for_each_entry_safe(next, tmp, &wq->flusher_queue, list) {
//			if (next->flush_color != wq->flush_color)
//				break;
//			list_del_init(&next->list);
//			complete(&next->done);
//		}

//		WARN_ON_ONCE(!list_empty(&wq->flusher_overflow) &&
//			     wq->flush_color != work_next_color(wq->work_color));

//		/* this flush_color is finished, advance by one */
//		wq->flush_color = work_next_color(wq->flush_color);

//		/* one color has been freed, handle overflow queue */
//		if (!list_empty(&wq->flusher_overflow)) {
//			/*
//			 * Assign the same color to all overflowed
//			 * flushers, advance work_color and append to
//			 * flusher_queue.  This is the start-to-wait
//			 * phase for these overflowed flushers.
//			 */
//			list_for_each_entry(tmp, &wq->flusher_overflow, list)
//				tmp->flush_color = wq->work_color;

//			wq->work_color = work_next_color(wq->work_color);

//			list_splice_tail_init(&wq->flusher_overflow,
//					      &wq->flusher_queue);
//			flush_workqueue_prep_pwqs(wq, -1, wq->work_color);
//		}

//		if (list_empty(&wq->flusher_queue)) {
//			WARN_ON_ONCE(wq->flush_color != wq->work_color);
//			break;
//		}

//		/*
//		 * Need to flush more colors.  Make the next flusher
//		 * the new first flusher and arm pwqs.
//		 */
//		WARN_ON_ONCE(wq->flush_color == wq->work_color);
//		WARN_ON_ONCE(wq->flush_color != next->flush_color);

//		list_del_init(&next->list);
//		wq->first_flusher = next;

//		if (flush_workqueue_prep_pwqs(wq, wq->flush_color, -1))
//			break;

//		/*
//		 * Meh... this color is already done, clear first
//		 * flusher and repeat cascading.
//		 */
//		wq->first_flusher = NULL;
//	}

//out_unlock:
//	mutex_unlock(&wq->mutex);
//}
//EXPORT_SYMBOL(flush_workqueue);

///**
// * drain_workqueue - drain a workqueue
// * @wq: workqueue to drain
// *
// * Wait until the workqueue becomes empty.  While draining is in progress,
// * only chain queueing is allowed.  IOW, only currently pending or running
// * work items on @wq can queue further work items on it.  @wq is flushed
// * repeatedly until it becomes empty.  The number of flushing is determined
// * by the depth of chaining and should be relatively short.  Whine if it
// * takes too long.
// */
//void drain_workqueue(struct workqueue_struct *wq)
//{
//	unsigned int flush_cnt = 0;
//	struct pool_workqueue *pwq;

//	/*
//	 * __queue_work() needs to test whether there are drainers, is much
//	 * hotter than drain_workqueue() and already looks at @wq->flags.
//	 * Use __WQ_DRAINING so that queue doesn't have to check nr_drainers.
//	 */
//	mutex_lock(&wq->mutex);
//	if (!wq->nr_drainers++)
//		wq->flags |= __WQ_DRAINING;
//	mutex_unlock(&wq->mutex);
//reflush:
//	flush_workqueue(wq);

//	mutex_lock(&wq->mutex);

//	for_each_pwq(pwq, wq) {
//		bool drained;

//		raw_spin_lock_irq(&pwq->pool->lock);
//		drained = !pwq->nr_active && list_empty(&pwq->delayed_works);
//		raw_spin_unlock_irq(&pwq->pool->lock);

//		if (drained)
//			continue;

//		if (++flush_cnt == 10 ||
//		    (flush_cnt % 100 == 0 && flush_cnt <= 1000))
//			pr_warn("workqueue %s: drain_workqueue() isn't complete after %u tries\n",
//				wq->name, flush_cnt);

//		mutex_unlock(&wq->mutex);
//		goto reflush;
//	}

//	if (!--wq->nr_drainers)
//		wq->flags &= ~__WQ_DRAINING;
//	mutex_unlock(&wq->mutex);
//}
//EXPORT_SYMBOL_GPL(drain_workqueue);

//static bool start_flush_work(struct work_struct *work, struct wq_barrier *barr,
//			     bool from_cancel)
//{
//	struct worker *worker = NULL;
//	struct worker_pool *pool;
//	struct pool_workqueue *pwq;

//	might_sleep();

//	rcu_read_lock();
//	pool = get_work_pool(work);
//	if (!pool) {
//		rcu_read_unlock();
//		return false;
//	}

//	raw_spin_lock_irq(&pool->lock);
//	/* see the comment in try_to_grab_pending() with the same code */
//	pwq = get_work_pwq(work);
//	if (pwq) {
//		if (unlikely(pwq->pool != pool))
//			goto already_gone;
//	} else {
//		worker = find_worker_executing_work(pool, work);
//		if (!worker)
//			goto already_gone;
//		pwq = worker->current_pwq;
//	}

//	check_flush_dependency(pwq->wq, work);

//	insert_wq_barrier(pwq, barr, work, worker);
//	raw_spin_unlock_irq(&pool->lock);

//	/*
//	 * Force a lock recursion deadlock when using flush_work() inside a
//	 * single-threaded or rescuer equipped workqueue.
//	 *
//	 * For single threaded workqueues the deadlock happens when the work
//	 * is after the work issuing the flush_work(). For rescuer equipped
//	 * workqueues the deadlock happens when the rescuer stalls, blocking
//	 * forward progress.
//	 */
//	if (!from_cancel &&
//	    (pwq->wq->saved_max_active == 1 || pwq->wq->rescuer)) {
//		lock_map_acquire(&pwq->wq->lockdep_map);
//		lock_map_release(&pwq->wq->lockdep_map);
//	}
//	rcu_read_unlock();
//	return true;
//already_gone:
//	raw_spin_unlock_irq(&pool->lock);
//	rcu_read_unlock();
//	return false;
//}

static bool __flush_work(struct work_struct *work, bool from_cancel)
{
//	struct wq_barrier barr;

//	if (WARN_ON(!wq_online))
//		return false;

//	if (WARN_ON(!work->func))
//		return false;

//	if (!from_cancel) {
//		lock_map_acquire(&work->lockdep_map);
//		lock_map_release(&work->lockdep_map);
//	}

//	if (start_flush_work(work, &barr, from_cancel)) {
//		wait_for_completion(&barr.done);
//		destroy_work_on_stack(&barr.work);
		return true;
//	} else {
//		return false;
//	}
}

/**
 * flush_work - wait for a work to finish executing the last queueing instance
 * @work: the work to flush
 *
 * Wait until @work has finished execution.  @work is guaranteed to be idle
 * on return if it hasn't been requeued since flush started.
 *
 * Return:
 * %true if flush_work() waited for the work to finish execution,
 * %false if it was already idle.
 */
bool flush_work(struct work_struct *work)
{
	return __flush_work(work, false);
}
EXPORT_SYMBOL_GPL(flush_work);

//struct cwt_wait {
//	wait_queue_entry_t		wait;
//	struct work_struct	*work;
//};

//static int cwt_wakefn(wait_queue_entry_t *wait, unsigned mode, int sync, void *key)
//{
//	struct cwt_wait *cwait = container_of(wait, struct cwt_wait, wait);

//	if (cwait->work != key)
//		return 0;
//	return autoremove_wake_function(wait, mode, sync, key);
//}

//static bool __cancel_work_timer(struct work_struct *work, bool is_dwork)
//{
//	static DECLARE_WAIT_QUEUE_HEAD(cancel_waitq);
//	unsigned long flags;
//	int ret;

//	do {
//		ret = try_to_grab_pending(work, is_dwork, &flags);
//		/*
//		 * If someone else is already canceling, wait for it to
//		 * finish.  flush_work() doesn't work for PREEMPT_NONE
//		 * because we may get scheduled between @work's completion
//		 * and the other canceling task resuming and clearing
//		 * CANCELING - flush_work() will return false immediately
//		 * as @work is no longer busy, try_to_grab_pending() will
//		 * return -ENOENT as @work is still being canceled and the
//		 * other canceling task won't be able to clear CANCELING as
//		 * we're hogging the CPU.
//		 *
//		 * Let's wait for completion using a waitqueue.  As this
//		 * may lead to the thundering herd problem, use a custom
//		 * wake function which matches @work along with exclusive
//		 * wait and wakeup.
//		 */
//		if (unlikely(ret == -ENOENT)) {
//			struct cwt_wait cwait;

//			init_wait(&cwait.wait);
//			cwait.wait.func = cwt_wakefn;
//			cwait.work = work;

//			prepare_to_wait_exclusive(&cancel_waitq, &cwait.wait,
//						  TASK_UNINTERRUPTIBLE);
//			if (work_is_canceling(work))
//				schedule();
//			finish_wait(&cancel_waitq, &cwait.wait);
//		}
//	} while (unlikely(ret < 0));

//	/* tell other tasks trying to grab @work to back off */
//	mark_work_canceling(work);
//	local_irq_restore(flags);

//	/*
//	 * This allows canceling during early boot.  We know that @work
//	 * isn't executing.
//	 */
//	if (wq_online)
//		__flush_work(work, true);

//	clear_work_data(work);

//	/*
//	 * Paired with prepare_to_wait() above so that either
//	 * waitqueue_active() is visible here or !work_is_canceling() is
//	 * visible there.
//	 */
//	smp_mb();
//	if (waitqueue_active(&cancel_waitq))
//		__wake_up(&cancel_waitq, TASK_NORMAL, 1, work);

//	return ret;
//}

///**
// * cancel_work_sync - cancel a work and wait for it to finish
// * @work: the work to cancel
// *
// * Cancel @work and wait for its execution to finish.  This function
// * can be used even if the work re-queues itself or migrates to
// * another workqueue.  On return from this function, @work is
// * guaranteed to be not pending or executing on any CPU.
// *
// * cancel_work_sync(&delayed_work->work) must not be used for
// * delayed_work's.  Use cancel_delayed_work_sync() instead.
// *
// * The caller must ensure that the workqueue on which @work was last
// * queued can't be destroyed before this function returns.
// *
// * Return:
// * %true if @work was pending, %false otherwise.
// */
//bool cancel_work_sync(struct work_struct *work)
//{
//	return __cancel_work_timer(work, false);
//}
//EXPORT_SYMBOL_GPL(cancel_work_sync);

///**
// * flush_delayed_work - wait for a dwork to finish executing the last queueing
// * @dwork: the delayed work to flush
// *
// * Delayed timer is cancelled and the pending work is queued for
// * immediate execution.  Like flush_work(), this function only
// * considers the last queueing instance of @dwork.
// *
// * Return:
// * %true if flush_work() waited for the work to finish execution,
// * %false if it was already idle.
// */
//bool flush_delayed_work(struct delayed_work *dwork)
//{
//	local_irq_disable();
//	if (del_timer_sync(&dwork->timer))
//		__queue_work(dwork->cpu, dwork->wq, &dwork->work);
//	local_irq_enable();
//	return flush_work(&dwork->work);
//}
//EXPORT_SYMBOL(flush_delayed_work);

///**
// * flush_rcu_work - wait for a rwork to finish executing the last queueing
// * @rwork: the rcu work to flush
// *
// * Return:
// * %true if flush_rcu_work() waited for the work to finish execution,
// * %false if it was already idle.
// */
//bool flush_rcu_work(struct rcu_work *rwork)
//{
//	if (test_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(&rwork->work))) {
//		rcu_barrier();
//		flush_work(&rwork->work);
//		return true;
//	} else {
//		return flush_work(&rwork->work);
//	}
//}
//EXPORT_SYMBOL(flush_rcu_work);

//static bool __cancel_work(struct work_struct *work, bool is_dwork)
//{
//	unsigned long flags;
//	int ret;

//	do {
//		ret = try_to_grab_pending(work, is_dwork, &flags);
//	} while (unlikely(ret == -EAGAIN));

//	if (unlikely(ret < 0))
//		return false;

//	set_work_pool_and_clear_pending(work, get_work_pool_id(work));
//	local_irq_restore(flags);
//	return ret;
//}

///**
// * cancel_delayed_work - cancel a delayed work
// * @dwork: delayed_work to cancel
// *
// * Kill off a pending delayed_work.
// *
// * Return: %true if @dwork was pending and canceled; %false if it wasn't
// * pending.
// *
// * Note:
// * The work callback function may still be running on return, unless
// * it returns %true and the work doesn't re-arm itself.  Explicitly flush or
// * use cancel_delayed_work_sync() to wait on it.
// *
// * This function is safe to call from any context including IRQ handler.
// */
//bool cancel_delayed_work(struct delayed_work *dwork)
//{
//	return __cancel_work(&dwork->work, true);
//}
//EXPORT_SYMBOL(cancel_delayed_work);

///**
// * cancel_delayed_work_sync - cancel a delayed work and wait for it to finish
// * @dwork: the delayed work cancel
// *
// * This is cancel_work_sync() for delayed works.
// *
// * Return:
// * %true if @dwork was pending, %false otherwise.
// */
//bool cancel_delayed_work_sync(struct delayed_work *dwork)
//{
//	return __cancel_work_timer(&dwork->work, true);
//}
//EXPORT_SYMBOL(cancel_delayed_work_sync);

///**
// * schedule_on_each_cpu - execute a function synchronously on each online CPU
// * @func: the function to call
// *
// * schedule_on_each_cpu() executes @func on each online CPU using the
// * system workqueue and blocks until all CPUs have completed.
// * schedule_on_each_cpu() is very slow.
// *
// * Return:
// * 0 on success, -errno on failure.
// */
//int schedule_on_each_cpu(work_func_t func)
//{
//	int cpu;
//	struct work_struct __percpu *works;

//	works = alloc_percpu(struct work_struct);
//	if (!works)
//		return -ENOMEM;

//	get_online_cpus();

//	for_each_online_cpu(cpu) {
//		struct work_struct *work = per_cpu_ptr(works, cpu);

//		INIT_WORK(work, func);
//		schedule_work_on(cpu, work);
//	}

//	for_each_online_cpu(cpu)
//		flush_work(per_cpu_ptr(works, cpu));

//	put_online_cpus();
//	free_percpu(works);
//	return 0;
//}

///**
// * execute_in_process_context - reliably execute the routine with user context
// * @fn:		the function to execute
// * @ew:		guaranteed storage for the execute work structure (must
// *		be available when the work executes)
// *
// * Executes the function immediately if process context is available,
// * otherwise schedules the function for delayed execution.
// *
// * Return:	0 - function was executed
// *		1 - function was scheduled for execution
// */
//int execute_in_process_context(work_func_t fn, struct execute_work *ew)
//{
//	if (!in_interrupt()) {
//		fn(&ew->work);
//		return 0;
//	}

//	INIT_WORK(&ew->work, fn);
//	schedule_work(&ew->work);

//	return 1;
//}
//EXPORT_SYMBOL_GPL(execute_in_process_context);

///**
// * free_workqueue_attrs - free a workqueue_attrs
// * @attrs: workqueue_attrs to free
// *
// * Undo alloc_workqueue_attrs().
// */
//void free_workqueue_attrs(struct workqueue_attrs *attrs)
//{
//	if (attrs) {
//		free_cpumask_var(attrs->cpumask);
//		kfree(attrs);
//	}
//}

///**
// * alloc_workqueue_attrs - allocate a workqueue_attrs
// *
// * Allocate a new workqueue_attrs, initialize with default settings and
// * return it.
// *
// * Return: The allocated new workqueue_attr on success. %NULL on failure.
// */
//struct workqueue_attrs *alloc_workqueue_attrs(void)
//{
//	struct workqueue_attrs *attrs;

//	attrs = kzalloc(sizeof(*attrs), GFP_KERNEL);
//	if (!attrs)
//		goto fail;
//	if (!alloc_cpumask_var(&attrs->cpumask, GFP_KERNEL))
//		goto fail;

//	cpumask_copy(attrs->cpumask, cpu_possible_mask);
//	return attrs;
//fail:
//	free_workqueue_attrs(attrs);
//	return NULL;
//}

//static void copy_workqueue_attrs(struct workqueue_attrs *to,
//				 const struct workqueue_attrs *from)
//{
//	to->nice = from->nice;
//	cpumask_copy(to->cpumask, from->cpumask);
//	/*
//	 * Unlike hash and equality test, this function doesn't ignore
//	 * ->no_numa as it is used for both pool and wq attrs.  Instead,
//	 * get_unbound_pool() explicitly clears ->no_numa after copying.
//	 */
//	to->no_numa = from->no_numa;
//}

///* hash value of the content of @attr */
//static u32 wqattrs_hash(const struct workqueue_attrs *attrs)
//{
//	u32 hash = 0;

//	hash = jhash_1word(attrs->nice, hash);
//	hash = jhash(cpumask_bits(attrs->cpumask),
//		     BITS_TO_LONGS(nr_cpumask_bits) * sizeof(long), hash);
//	return hash;
//}

///* content equality test */
//static bool wqattrs_equal(const struct workqueue_attrs *a,
//			  const struct workqueue_attrs *b)
//{
//	if (a->nice != b->nice)
//		return false;
//	if (!cpumask_equal(a->cpumask, b->cpumask))
//		return false;
//	return true;
//}

///**
// * init_worker_pool - initialize a newly zalloc'd worker_pool
// * @pool: worker_pool to initialize
// *
// * Initialize a newly zalloc'd @pool.  It also allocates @pool->attrs.
// *
// * Return: 0 on success, -errno on failure.  Even on failure, all fields
// * inside @pool proper are initialized and put_unbound_pool() can be called
// * on @pool safely to release it.
// */
//static int init_worker_pool(struct worker_pool *pool)
//{
//	raw_spin_lock_init(&pool->lock);
//	pool->id = -1;
//	pool->cpu = -1;
//	pool->node = NUMA_NO_NODE;
//	pool->flags |= POOL_DISASSOCIATED;
//	pool->watchdog_ts = jiffies;
//	INIT_LIST_HEAD(&pool->worklist);
//	INIT_LIST_HEAD(&pool->idle_list);
//	hash_init(pool->busy_hash);

//	timer_setup(&pool->idle_timer, idle_worker_timeout, TIMER_DEFERRABLE);

//	timer_setup(&pool->mayday_timer, pool_mayday_timeout, 0);

//	INIT_LIST_HEAD(&pool->workers);

//	ida_init(&pool->worker_ida);
//	INIT_HLIST_NODE(&pool->hash_node);
//	pool->refcnt = 1;

//	/* shouldn't fail above this point */
//	pool->attrs = alloc_workqueue_attrs();
//	if (!pool->attrs)
//		return -ENOMEM;
//	return 0;
//}

//#ifdef CONFIG_LOCKDEP
//static void wq_init_lockdep(struct workqueue_struct *wq)
//{
//	char *lock_name;

//	lockdep_register_key(&wq->key);
//	lock_name = kasprintf(GFP_KERNEL, "%s%s", "(wq_completion)", wq->name);
//	if (!lock_name)
//		lock_name = wq->name;

//	wq->lock_name = lock_name;
//	lockdep_init_map(&wq->lockdep_map, lock_name, &wq->key, 0);
//}

//static void wq_unregister_lockdep(struct workqueue_struct *wq)
//{
//	lockdep_unregister_key(&wq->key);
//}

//static void wq_free_lockdep(struct workqueue_struct *wq)
//{
//	if (wq->lock_name != wq->name)
//		kfree(wq->lock_name);
//}
//#else
//static void wq_init_lockdep(struct workqueue_struct *wq)
//{
//}

//static void wq_unregister_lockdep(struct workqueue_struct *wq)
//{
//}

//static void wq_free_lockdep(struct workqueue_struct *wq)
//{
//}
//#endif

//static void rcu_free_wq(struct rcu_head *rcu)
//{
//	struct workqueue_struct *wq =
//		container_of(rcu, struct workqueue_struct, rcu);

//	wq_free_lockdep(wq);

//	if (!(wq->flags & WQ_UNBOUND))
//		free_percpu(wq->cpu_pwqs);
//	else
//		free_workqueue_attrs(wq->unbound_attrs);

//	kfree(wq);
//}

//static void rcu_free_pool(struct rcu_head *rcu)
//{
//	struct worker_pool *pool = container_of(rcu, struct worker_pool, rcu);

//	ida_destroy(&pool->worker_ida);
//	free_workqueue_attrs(pool->attrs);
//	kfree(pool);
//}

///* This returns with the lock held on success (pool manager is inactive). */
//static bool wq_manager_inactive(struct worker_pool *pool)
//{
//	raw_spin_lock_irq(&pool->lock);

//	if (pool->flags & POOL_MANAGER_ACTIVE) {
//		raw_spin_unlock_irq(&pool->lock);
//		return false;
//	}
//	return true;
//}

///**
// * put_unbound_pool - put a worker_pool
// * @pool: worker_pool to put
// *
// * Put @pool.  If its refcnt reaches zero, it gets destroyed in RCU
// * safe manner.  get_unbound_pool() calls this function on its failure path
// * and this function should be able to release pools which went through,
// * successfully or not, init_worker_pool().
// *
// * Should be called with wq_pool_mutex held.
// */
//static void put_unbound_pool(struct worker_pool *pool)
//{
//	DECLARE_COMPLETION_ONSTACK(detach_completion);
//	struct worker *worker;

//	lockdep_assert_held(&wq_pool_mutex);

//	if (--pool->refcnt)
//		return;

//	/* sanity checks */
//	if (WARN_ON(!(pool->cpu < 0)) ||
//	    WARN_ON(!list_empty(&pool->worklist)))
//		return;

//	/* release id and unhash */
//	if (pool->id >= 0)
//		idr_remove(&worker_pool_idr, pool->id);
//	hash_del(&pool->hash_node);

//	/*
//	 * Become the manager and destroy all workers.  This prevents
//	 * @pool's workers from blocking on attach_mutex.  We're the last
//	 * manager and @pool gets freed with the flag set.
//	 * Because of how wq_manager_inactive() works, we will hold the
//	 * spinlock after a successful wait.
//	 */
//	rcuwait_wait_event(&manager_wait, wq_manager_inactive(pool),
//			   TASK_UNINTERRUPTIBLE);
//	pool->flags |= POOL_MANAGER_ACTIVE;

//	while ((worker = first_idle_worker(pool)))
//		destroy_worker(worker);
//	WARN_ON(pool->nr_workers || pool->nr_idle);
//	raw_spin_unlock_irq(&pool->lock);

//	mutex_lock(&wq_pool_attach_mutex);
//	if (!list_empty(&pool->workers))
//		pool->detach_completion = &detach_completion;
//	mutex_unlock(&wq_pool_attach_mutex);

//	if (pool->detach_completion)
//		wait_for_completion(pool->detach_completion);

//	/* shut down the timers */
//	del_timer_sync(&pool->idle_timer);
//	del_timer_sync(&pool->mayday_timer);

//	/* RCU protected to allow dereferences from get_work_pool() */
//	call_rcu(&pool->rcu, rcu_free_pool);
//}

///**
// * get_unbound_pool - get a worker_pool with the specified attributes
// * @attrs: the attributes of the worker_pool to get
// *
// * Obtain a worker_pool which has the same attributes as @attrs, bump the
// * reference count and return it.  If there already is a matching
// * worker_pool, it will be used; otherwise, this function attempts to
// * create a new one.
// *
// * Should be called with wq_pool_mutex held.
// *
// * Return: On success, a worker_pool with the same attributes as @attrs.
// * On failure, %NULL.
// */
//static struct worker_pool *get_unbound_pool(const struct workqueue_attrs *attrs)
//{
//	u32 hash = wqattrs_hash(attrs);
//	struct worker_pool *pool;
//	int node;
//	int target_node = NUMA_NO_NODE;

//	lockdep_assert_held(&wq_pool_mutex);

//	/* do we already have a matching pool? */
//	hash_for_each_possible(unbound_pool_hash, pool, hash_node, hash) {
//		if (wqattrs_equal(pool->attrs, attrs)) {
//			pool->refcnt++;
//			return pool;
//		}
//	}

//	/* if cpumask is contained inside a NUMA node, we belong to that node */
//	if (wq_numa_enabled) {
//		for_each_node(node) {
//			if (cpumask_subset(attrs->cpumask,
//					   wq_numa_possible_cpumask[node])) {
//				target_node = node;
//				break;
//			}
//		}
//	}

//	/* nope, create a new one */
//	pool = kzalloc_node(sizeof(*pool), GFP_KERNEL, target_node);
//	if (!pool || init_worker_pool(pool) < 0)
//		goto fail;

//	lockdep_set_subclass(&pool->lock, 1);	/* see put_pwq() */
//	copy_workqueue_attrs(pool->attrs, attrs);
//	pool->node = target_node;

//	/*
//	 * no_numa isn't a worker_pool attribute, always clear it.  See
//	 * 'struct workqueue_attrs' comments for detail.
//	 */
//	pool->attrs->no_numa = false;

//	if (worker_pool_assign_id(pool) < 0)
//		goto fail;

//	/* create and start the initial worker */
//	if (wq_online && !create_worker(pool))
//		goto fail;

//	/* install */
//	hash_add(unbound_pool_hash, &pool->hash_node, hash);

//	return pool;
//fail:
//	if (pool)
//		put_unbound_pool(pool);
//	return NULL;
//}

//static void rcu_free_pwq(struct rcu_head *rcu)
//{
//	kmem_cache_free(pwq_cache,
//			container_of(rcu, struct pool_workqueue, rcu));
//}

///*
// * Scheduled on system_wq by put_pwq() when an unbound pwq hits zero refcnt
// * and needs to be destroyed.
// */
//static void pwq_unbound_release_workfn(struct work_struct *work)
//{
//	struct pool_workqueue *pwq = container_of(work, struct pool_workqueue,
//						  unbound_release_work);
//	struct workqueue_struct *wq = pwq->wq;
//	struct worker_pool *pool = pwq->pool;
//	bool is_last;

//	if (WARN_ON_ONCE(!(wq->flags & WQ_UNBOUND)))
//		return;

//	mutex_lock(&wq->mutex);
//	list_del_rcu(&pwq->pwqs_node);
//	is_last = list_empty(&wq->pwqs);
//	mutex_unlock(&wq->mutex);

//	mutex_lock(&wq_pool_mutex);
//	put_unbound_pool(pool);
//	mutex_unlock(&wq_pool_mutex);

//	call_rcu(&pwq->rcu, rcu_free_pwq);

//	/*
//	 * If we're the last pwq going away, @wq is already dead and no one
//	 * is gonna access it anymore.  Schedule RCU free.
//	 */
//	if (is_last) {
//		wq_unregister_lockdep(wq);
//		call_rcu(&wq->rcu, rcu_free_wq);
//	}
//}

///**
// * pwq_adjust_max_active - update a pwq's max_active to the current setting
// * @pwq: target pool_workqueue
// *
// * If @pwq isn't freezing, set @pwq->max_active to the associated
// * workqueue's saved_max_active and activate delayed work items
// * accordingly.  If @pwq is freezing, clear @pwq->max_active to zero.
// */
//static void pwq_adjust_max_active(struct pool_workqueue *pwq)
//{
//	struct workqueue_struct *wq = pwq->wq;
//	bool freezable = wq->flags & WQ_FREEZABLE;
//	unsigned long flags;

//	/* for @wq->saved_max_active */
//	lockdep_assert_held(&wq->mutex);

//	/* fast exit for non-freezable wqs */
//	if (!freezable && pwq->max_active == wq->saved_max_active)
//		return;

//	/* this function can be called during early boot w/ irq disabled */
//	raw_spin_lock_irqsave(&pwq->pool->lock, flags);

//	/*
//	 * During [un]freezing, the caller is responsible for ensuring that
//	 * this function is called at least once after @workqueue_freezing
//	 * is updated and visible.
//	 */
//	if (!freezable || !workqueue_freezing) {
//		bool kick = false;

//		pwq->max_active = wq->saved_max_active;

//		while (!list_empty(&pwq->delayed_works) &&
//		       pwq->nr_active < pwq->max_active) {
//			pwq_activate_first_delayed(pwq);
//			kick = true;
//		}

//		/*
//		 * Need to kick a worker after thawed or an unbound wq's
//		 * max_active is bumped. In realtime scenarios, always kicking a
//		 * worker will cause interference on the isolated cpu cores, so
//		 * let's kick iff work items were activated.
//		 */
//		if (kick)
//			wake_up_worker(pwq->pool);
//	} else {
//		pwq->max_active = 0;
//	}

//	raw_spin_unlock_irqrestore(&pwq->pool->lock, flags);
//}

///* initialize newly alloced @pwq which is associated with @wq and @pool */
//static void init_pwq(struct pool_workqueue *pwq, struct workqueue_struct *wq,
//		     struct worker_pool *pool)
//{
//	BUG_ON((unsigned long)pwq & WORK_STRUCT_FLAG_MASK);

//	memset(pwq, 0, sizeof(*pwq));

//	pwq->pool = pool;
//	pwq->wq = wq;
//	pwq->flush_color = -1;
//	pwq->refcnt = 1;
//	INIT_LIST_HEAD(&pwq->delayed_works);
//	INIT_LIST_HEAD(&pwq->pwqs_node);
//	INIT_LIST_HEAD(&pwq->mayday_node);
//	INIT_WORK(&pwq->unbound_release_work, pwq_unbound_release_workfn);
//}

///* sync @pwq with the current state of its associated wq and link it */
//static void link_pwq(struct pool_workqueue *pwq)
//{
//	struct workqueue_struct *wq = pwq->wq;

//	lockdep_assert_held(&wq->mutex);

//	/* may be called multiple times, ignore if already linked */
//	if (!list_empty(&pwq->pwqs_node))
//		return;

//	/* set the matching work_color */
//	pwq->work_color = wq->work_color;

//	/* sync max_active to the current setting */
//	pwq_adjust_max_active(pwq);

//	/* link in @pwq */
//	list_add_rcu(&pwq->pwqs_node, &wq->pwqs);
//}

///* obtain a pool matching @attr and create a pwq associating the pool and @wq */
//static struct pool_workqueue *alloc_unbound_pwq(struct workqueue_struct *wq,
//					const struct workqueue_attrs *attrs)
//{
//	struct worker_pool *pool;
//	struct pool_workqueue *pwq;

//	lockdep_assert_held(&wq_pool_mutex);

//	pool = get_unbound_pool(attrs);
//	if (!pool)
//		return NULL;

//	pwq = kmem_cache_alloc_node(pwq_cache, GFP_KERNEL, pool->node);
//	if (!pwq) {
//		put_unbound_pool(pool);
//		return NULL;
//	}

//	init_pwq(pwq, wq, pool);
//	return pwq;
//}

///**
// * wq_calc_node_cpumask - calculate a wq_attrs' cpumask for the specified node
// * @attrs: the wq_attrs of the default pwq of the target workqueue
// * @node: the target NUMA node
// * @cpu_going_down: if >= 0, the CPU to consider as offline
// * @cpumask: outarg, the resulting cpumask
// *
// * Calculate the cpumask a workqueue with @attrs should use on @node.  If
// * @cpu_going_down is >= 0, that cpu is considered offline during
// * calculation.  The result is stored in @cpumask.
// *
// * If NUMA affinity is not enabled, @attrs->cpumask is always used.  If
// * enabled and @node has online CPUs requested by @attrs, the returned
// * cpumask is the intersection of the possible CPUs of @node and
// * @attrs->cpumask.
// *
// * The caller is responsible for ensuring that the cpumask of @node stays
// * stable.
// *
// * Return: %true if the resulting @cpumask is different from @attrs->cpumask,
// * %false if equal.
// */
//static bool wq_calc_node_cpumask(const struct workqueue_attrs *attrs, int node,
//				 int cpu_going_down, cpumask_t *cpumask)
//{
//	if (!wq_numa_enabled || attrs->no_numa)
//		goto use_dfl;

//	/* does @node have any online CPUs @attrs wants? */
//	cpumask_and(cpumask, cpumask_of_node(node), attrs->cpumask);
//	if (cpu_going_down >= 0)
//		cpumask_clear_cpu(cpu_going_down, cpumask);

//	if (cpumask_empty(cpumask))
//		goto use_dfl;

//	/* yeap, return possible CPUs in @node that @attrs wants */
//	cpumask_and(cpumask, attrs->cpumask, wq_numa_possible_cpumask[node]);

//	if (cpumask_empty(cpumask)) {
//		pr_warn_once("WARNING: workqueue cpumask: online intersect > "
//				"possible intersect\n");
//		return false;
//	}

//	return !cpumask_equal(cpumask, attrs->cpumask);

//use_dfl:
//	cpumask_copy(cpumask, attrs->cpumask);
//	return false;
//}

///* install @pwq into @wq's numa_pwq_tbl[] for @node and return the old pwq */
//static struct pool_workqueue *numa_pwq_tbl_install(struct workqueue_struct *wq,
//						   int node,
//						   struct pool_workqueue *pwq)
//{
//	struct pool_workqueue *old_pwq;

//	lockdep_assert_held(&wq_pool_mutex);
//	lockdep_assert_held(&wq->mutex);

//	/* link_pwq() can handle duplicate calls */
//	link_pwq(pwq);

//	old_pwq = rcu_access_pointer(wq->numa_pwq_tbl[node]);
//	rcu_assign_pointer(wq->numa_pwq_tbl[node], pwq);
//	return old_pwq;
//}

///* context to store the prepared attrs & pwqs before applying */
//struct apply_wqattrs_ctx {
//	struct workqueue_struct	*wq;		/* target workqueue */
//	struct workqueue_attrs	*attrs;		/* attrs to apply */
//	struct list_head	list;		/* queued for batching commit */
//	struct pool_workqueue	*dfl_pwq;
//	struct pool_workqueue	*pwq_tbl[];
//};

///* free the resources after success or abort */
//static void apply_wqattrs_cleanup(struct apply_wqattrs_ctx *ctx)
//{
//	if (ctx) {
//		int node;

//		for_each_node(node)
//			put_pwq_unlocked(ctx->pwq_tbl[node]);
//		put_pwq_unlocked(ctx->dfl_pwq);

//		free_workqueue_attrs(ctx->attrs);

//		kfree(ctx);
//	}
//}

///* allocate the attrs and pwqs for later installation */
//static struct apply_wqattrs_ctx *
//apply_wqattrs_prepare(struct workqueue_struct *wq,
//		      const struct workqueue_attrs *attrs)
//{
//	struct apply_wqattrs_ctx *ctx;
//	struct workqueue_attrs *new_attrs, *tmp_attrs;
//	int node;

//	lockdep_assert_held(&wq_pool_mutex);

//	ctx = kzalloc(struct_size(ctx, pwq_tbl, nr_node_ids), GFP_KERNEL);

//	new_attrs = alloc_workqueue_attrs();
//	tmp_attrs = alloc_workqueue_attrs();
//	if (!ctx || !new_attrs || !tmp_attrs)
//		goto out_free;

//	/*
//	 * Calculate the attrs of the default pwq.
//	 * If the user configured cpumask doesn't overlap with the
//	 * wq_unbound_cpumask, we fallback to the wq_unbound_cpumask.
//	 */
//	copy_workqueue_attrs(new_attrs, attrs);
//	cpumask_and(new_attrs->cpumask, new_attrs->cpumask, wq_unbound_cpumask);
//	if (unlikely(cpumask_empty(new_attrs->cpumask)))
//		cpumask_copy(new_attrs->cpumask, wq_unbound_cpumask);

//	/*
//	 * We may create multiple pwqs with differing cpumasks.  Make a
//	 * copy of @new_attrs which will be modified and used to obtain
//	 * pools.
//	 */
//	copy_workqueue_attrs(tmp_attrs, new_attrs);

//	/*
//	 * If something goes wrong during CPU up/down, we'll fall back to
//	 * the default pwq covering whole @attrs->cpumask.  Always create
//	 * it even if we don't use it immediately.
//	 */
//	ctx->dfl_pwq = alloc_unbound_pwq(wq, new_attrs);
//	if (!ctx->dfl_pwq)
//		goto out_free;

//	for_each_node(node) {
//		if (wq_calc_node_cpumask(new_attrs, node, -1, tmp_attrs->cpumask)) {
//			ctx->pwq_tbl[node] = alloc_unbound_pwq(wq, tmp_attrs);
//			if (!ctx->pwq_tbl[node])
//				goto out_free;
//		} else {
//			ctx->dfl_pwq->refcnt++;
//			ctx->pwq_tbl[node] = ctx->dfl_pwq;
//		}
//	}

//	/* save the user configured attrs and sanitize it. */
//	copy_workqueue_attrs(new_attrs, attrs);
//	cpumask_and(new_attrs->cpumask, new_attrs->cpumask, cpu_possible_mask);
//	ctx->attrs = new_attrs;

//	ctx->wq = wq;
//	free_workqueue_attrs(tmp_attrs);
//	return ctx;

//out_free:
//	free_workqueue_attrs(tmp_attrs);
//	free_workqueue_attrs(new_attrs);
//	apply_wqattrs_cleanup(ctx);
//	return NULL;
//}

///* set attrs and install prepared pwqs, @ctx points to old pwqs on return */
//static void apply_wqattrs_commit(struct apply_wqattrs_ctx *ctx)
//{
//	int node;

//	/* all pwqs have been created successfully, let's install'em */
//	mutex_lock(&ctx->wq->mutex);

//	copy_workqueue_attrs(ctx->wq->unbound_attrs, ctx->attrs);

//	/* save the previous pwq and install the new one */
//	for_each_node(node)
//		ctx->pwq_tbl[node] = numa_pwq_tbl_install(ctx->wq, node,
//							  ctx->pwq_tbl[node]);

//	/* @dfl_pwq might not have been used, ensure it's linked */
//	link_pwq(ctx->dfl_pwq);
//	swap(ctx->wq->dfl_pwq, ctx->dfl_pwq);

//	mutex_unlock(&ctx->wq->mutex);
//}

//static void apply_wqattrs_lock(void)
//{
//	/* CPUs should stay stable across pwq creations and installations */
//	get_online_cpus();
//	mutex_lock(&wq_pool_mutex);
//}

//static void apply_wqattrs_unlock(void)
//{
//	mutex_unlock(&wq_pool_mutex);
//	put_online_cpus();
//}

//static int apply_workqueue_attrs_locked(struct workqueue_struct *wq,
//					const struct workqueue_attrs *attrs)
//{
//	struct apply_wqattrs_ctx *ctx;

//	/* only unbound workqueues can change attributes */
//	if (WARN_ON(!(wq->flags & WQ_UNBOUND)))
//		return -EINVAL;

//	/* creating multiple pwqs breaks ordering guarantee */
//	if (!list_empty(&wq->pwqs)) {
//		if (WARN_ON(wq->flags & __WQ_ORDERED_EXPLICIT))
//			return -EINVAL;

//		wq->flags &= ~__WQ_ORDERED;
//	}

//	ctx = apply_wqattrs_prepare(wq, attrs);
//	if (!ctx)
//		return -ENOMEM;

//	/* the ctx has been prepared successfully, let's commit it */
//	apply_wqattrs_commit(ctx);
//	apply_wqattrs_cleanup(ctx);

//	return 0;
//}

///**
// * apply_workqueue_attrs - apply new workqueue_attrs to an unbound workqueue
// * @wq: the target workqueue
// * @attrs: the workqueue_attrs to apply, allocated with alloc_workqueue_attrs()
// *
// * Apply @attrs to an unbound workqueue @wq.  Unless disabled, on NUMA
// * machines, this function maps a separate pwq to each NUMA node with
// * possibles CPUs in @attrs->cpumask so that work items are affine to the
// * NUMA node it was issued on.  Older pwqs are released as in-flight work
// * items finish.  Note that a work item which repeatedly requeues itself
// * back-to-back will stay on its current pwq.
// *
// * Performs GFP_KERNEL allocations.
// *
// * Assumes caller has CPU hotplug read exclusion, i.e. get_online_cpus().
// *
// * Return: 0 on success and -errno on failure.
// */
//int apply_workqueue_attrs(struct workqueue_struct *wq,
//			  const struct workqueue_attrs *attrs)
//{
//	int ret;

//	lockdep_assert_cpus_held();

//	mutex_lock(&wq_pool_mutex);
//	ret = apply_workqueue_attrs_locked(wq, attrs);
//	mutex_unlock(&wq_pool_mutex);

//	return ret;
//}

///**
// * wq_update_unbound_numa - update NUMA affinity of a wq for CPU hot[un]plug
// * @wq: the target workqueue
// * @cpu: the CPU coming up or going down
// * @online: whether @cpu is coming up or going down
// *
// * This function is to be called from %CPU_DOWN_PREPARE, %CPU_ONLINE and
// * %CPU_DOWN_FAILED.  @cpu is being hot[un]plugged, update NUMA affinity of
// * @wq accordingly.
// *
// * If NUMA affinity can't be adjusted due to memory allocation failure, it
// * falls back to @wq->dfl_pwq which may not be optimal but is always
// * correct.
// *
// * Note that when the last allowed CPU of a NUMA node goes offline for a
// * workqueue with a cpumask spanning multiple nodes, the workers which were
// * already executing the work items for the workqueue will lose their CPU
// * affinity and may execute on any CPU.  This is similar to how per-cpu
// * workqueues behave on CPU_DOWN.  If a workqueue user wants strict
// * affinity, it's the user's responsibility to flush the work item from
// * CPU_DOWN_PREPARE.
// */
//static void wq_update_unbound_numa(struct workqueue_struct *wq, int cpu,
//				   bool online)
//{
//	int node = cpu_to_node(cpu);
//	int cpu_off = online ? -1 : cpu;
//	struct pool_workqueue *old_pwq = NULL, *pwq;
//	struct workqueue_attrs *target_attrs;
//	cpumask_t *cpumask;

//	lockdep_assert_held(&wq_pool_mutex);

//	if (!wq_numa_enabled || !(wq->flags & WQ_UNBOUND) ||
//	    wq->unbound_attrs->no_numa)
//		return;

//	/*
//	 * We don't wanna alloc/free wq_attrs for each wq for each CPU.
//	 * Let's use a preallocated one.  The following buf is protected by
//	 * CPU hotplug exclusion.
//	 */
//	target_attrs = wq_update_unbound_numa_attrs_buf;
//	cpumask = target_attrs->cpumask;

//	copy_workqueue_attrs(target_attrs, wq->unbound_attrs);
//	pwq = unbound_pwq_by_node(wq, node);

//	/*
//	 * Let's determine what needs to be done.  If the target cpumask is
//	 * different from the default pwq's, we need to compare it to @pwq's
//	 * and create a new one if they don't match.  If the target cpumask
//	 * equals the default pwq's, the default pwq should be used.
//	 */
//	if (wq_calc_node_cpumask(wq->dfl_pwq->pool->attrs, node, cpu_off, cpumask)) {
//		if (cpumask_equal(cpumask, pwq->pool->attrs->cpumask))
//			return;
//	} else {
//		goto use_dfl_pwq;
//	}

//	/* create a new pwq */
//	pwq = alloc_unbound_pwq(wq, target_attrs);
//	if (!pwq) {
//		pr_warn("workqueue: allocation failed while updating NUMA affinity of \"%s\"\n",
//			wq->name);
//		goto use_dfl_pwq;
//	}

//	/* Install the new pwq. */
//	mutex_lock(&wq->mutex);
//	old_pwq = numa_pwq_tbl_install(wq, node, pwq);
//	goto out_unlock;

//use_dfl_pwq:
//	mutex_lock(&wq->mutex);
//	raw_spin_lock_irq(&wq->dfl_pwq->pool->lock);
//	get_pwq(wq->dfl_pwq);
//	raw_spin_unlock_irq(&wq->dfl_pwq->pool->lock);
//	old_pwq = numa_pwq_tbl_install(wq, node, wq->dfl_pwq);
//out_unlock:
//	mutex_unlock(&wq->mutex);
//	put_pwq_unlocked(old_pwq);
//}

//static int alloc_and_link_pwqs(struct workqueue_struct *wq)
//{
//	bool highpri = wq->flags & WQ_HIGHPRI;
//	int cpu, ret;

//	if (!(wq->flags & WQ_UNBOUND)) {
//		wq->cpu_pwqs = alloc_percpu(struct pool_workqueue);
//		if (!wq->cpu_pwqs)
//			return -ENOMEM;

//		for_each_possible_cpu(cpu) {
//			struct pool_workqueue *pwq =
//				per_cpu_ptr(wq->cpu_pwqs, cpu);
//			struct worker_pool *cpu_pools =
//				per_cpu(cpu_worker_pools, cpu);

//			init_pwq(pwq, wq, &cpu_pools[highpri]);

//			mutex_lock(&wq->mutex);
//			link_pwq(pwq);
//			mutex_unlock(&wq->mutex);
//		}
//		return 0;
//	}

//	get_online_cpus();
//	if (wq->flags & __WQ_ORDERED) {
//		ret = apply_workqueue_attrs(wq, ordered_wq_attrs[highpri]);
//		/* there should only be single pwq for ordering guarantee */
//		WARN(!ret && (wq->pwqs.next != &wq->dfl_pwq->pwqs_node ||
//			      wq->pwqs.prev != &wq->dfl_pwq->pwqs_node),
//		     "ordering guarantee broken for workqueue %s\n", wq->name);
//	} else {
//		ret = apply_workqueue_attrs(wq, unbound_std_wq_attrs[highpri]);
//	}
//	put_online_cpus();

//	return ret;
//}

//static int wq_clamp_max_active(int max_active, unsigned int flags,
//			       const char *name)
//{
//	int lim = flags & WQ_UNBOUND ? WQ_UNBOUND_MAX_ACTIVE : WQ_MAX_ACTIVE;

//	if (max_active < 1 || max_active > lim)
//		pr_warn("workqueue: max_active %d requested for %s is out of range, clamping between %d and %d\n",
//			max_active, name, 1, lim);

//	return clamp_val(max_active, 1, lim);
//}

///*
// * Workqueues which may be used during memory reclaim should have a rescuer
// * to guarantee forward progress.
// */
//static int init_rescuer(struct workqueue_struct *wq)
//{
//	struct worker *rescuer;
//	int ret;

//	if (!(wq->flags & WQ_MEM_RECLAIM))
//		return 0;

//	rescuer = alloc_worker(NUMA_NO_NODE);
//	if (!rescuer)
//		return -ENOMEM;

//	rescuer->rescue_wq = wq;
//	rescuer->task = kthread_create(rescuer_thread, rescuer, "%s", wq->name);
//	if (IS_ERR(rescuer->task)) {
//		ret = PTR_ERR(rescuer->task);
//		kfree(rescuer);
//		return ret;
//	}

//	wq->rescuer = rescuer;
//	kthread_bind_mask(rescuer->task, cpu_possible_mask);
//	wake_up_process(rescuer->task);

//	return 0;
//}

//__printf(1, 4)
//struct workqueue_struct *alloc_workqueue(const char *fmt,
//					 unsigned int flags,
//					 int max_active, ...)
//{
//	size_t tbl_size = 0;
//	va_list args;
//	struct workqueue_struct *wq;
//	struct pool_workqueue *pwq;

//	/*
//	 * Unbound && max_active == 1 used to imply ordered, which is no
//	 * longer the case on NUMA machines due to per-node pools.  While
//	 * alloc_ordered_workqueue() is the right way to create an ordered
//	 * workqueue, keep the previous behavior to avoid subtle breakages
//	 * on NUMA.
//	 */
//	if ((flags & WQ_UNBOUND) && max_active == 1)
//		flags |= __WQ_ORDERED;

//	/* see the comment above the definition of WQ_POWER_EFFICIENT */
//	if ((flags & WQ_POWER_EFFICIENT) && wq_power_efficient)
//		flags |= WQ_UNBOUND;

//	/* allocate wq and format name */
//	if (flags & WQ_UNBOUND)
//		tbl_size = nr_node_ids * sizeof(wq->numa_pwq_tbl[0]);

//	wq = kzalloc(sizeof(*wq) + tbl_size, GFP_KERNEL);
//	if (!wq)
//		return NULL;

//	if (flags & WQ_UNBOUND) {
//		wq->unbound_attrs = alloc_workqueue_attrs();
//		if (!wq->unbound_attrs)
//			goto err_free_wq;
//	}

//	va_start(args, max_active);
//	vsnprintf(wq->name, sizeof(wq->name), fmt, args);
//	va_end(args);

//	max_active = max_active ?: WQ_DFL_ACTIVE;
//	max_active = wq_clamp_max_active(max_active, flags, wq->name);

//	/* init wq */
//	wq->flags = flags;
//	wq->saved_max_active = max_active;
//	mutex_init(&wq->mutex);
//	atomic_set(&wq->nr_pwqs_to_flush, 0);
//	INIT_LIST_HEAD(&wq->pwqs);
//	INIT_LIST_HEAD(&wq->flusher_queue);
//	INIT_LIST_HEAD(&wq->flusher_overflow);
//	INIT_LIST_HEAD(&wq->maydays);

//	wq_init_lockdep(wq);
//	INIT_LIST_HEAD(&wq->list);

//	if (alloc_and_link_pwqs(wq) < 0)
//		goto err_unreg_lockdep;

//	if (wq_online && init_rescuer(wq) < 0)
//		goto err_destroy;

//	if ((wq->flags & WQ_SYSFS) && workqueue_sysfs_register(wq))
//		goto err_destroy;

//	/*
//	 * wq_pool_mutex protects global freeze state and workqueues list.
//	 * Grab it, adjust max_active and add the new @wq to workqueues
//	 * list.
//	 */
//	mutex_lock(&wq_pool_mutex);

//	mutex_lock(&wq->mutex);
//	for_each_pwq(pwq, wq)
//		pwq_adjust_max_active(pwq);
//	mutex_unlock(&wq->mutex);

//	list_add_tail_rcu(&wq->list, &workqueues);

//	mutex_unlock(&wq_pool_mutex);

//	return wq;

//err_unreg_lockdep:
//	wq_unregister_lockdep(wq);
//	wq_free_lockdep(wq);
//err_free_wq:
//	free_workqueue_attrs(wq->unbound_attrs);
//	kfree(wq);
//	return NULL;
//err_destroy:
//	destroy_workqueue(wq);
//	return NULL;
//}
//EXPORT_SYMBOL_GPL(alloc_workqueue);

//static bool pwq_busy(struct pool_workqueue *pwq)
//{
//	int i;

//	for (i = 0; i < WORK_NR_COLORS; i++)
//		if (pwq->nr_in_flight[i])
//			return true;

//	if ((pwq != pwq->wq->dfl_pwq) && (pwq->refcnt > 1))
//		return true;
//	if (pwq->nr_active || !list_empty(&pwq->delayed_works))
//		return true;

//	return false;
//}

///**
// * destroy_workqueue - safely terminate a workqueue
// * @wq: target workqueue
// *
// * Safely destroy a workqueue. All work currently pending will be done first.
// */
//void destroy_workqueue(struct workqueue_struct *wq)
//{
//	struct pool_workqueue *pwq;
//	int node;

//	/*
//	 * Remove it from sysfs first so that sanity check failure doesn't
//	 * lead to sysfs name conflicts.
//	 */
//	workqueue_sysfs_unregister(wq);

//	/* drain it before proceeding with destruction */
//	drain_workqueue(wq);

//	/* kill rescuer, if sanity checks fail, leave it w/o rescuer */
//	if (wq->rescuer) {
//		struct worker *rescuer = wq->rescuer;

//		/* this prevents new queueing */
//		raw_spin_lock_irq(&wq_mayday_lock);
//		wq->rescuer = NULL;
//		raw_spin_unlock_irq(&wq_mayday_lock);

//		/* rescuer will empty maydays list before exiting */
//		kthread_stop(rescuer->task);
//		kfree(rescuer);
//	}

//	/*
//	 * Sanity checks - grab all the locks so that we wait for all
//	 * in-flight operations which may do put_pwq().
//	 */
//	mutex_lock(&wq_pool_mutex);
//	mutex_lock(&wq->mutex);
//	for_each_pwq(pwq, wq) {
//		raw_spin_lock_irq(&pwq->pool->lock);
//		if (WARN_ON(pwq_busy(pwq))) {
//			pr_warn("%s: %s has the following busy pwq\n",
//				__func__, wq->name);
//			show_pwq(pwq);
//			raw_spin_unlock_irq(&pwq->pool->lock);
//			mutex_unlock(&wq->mutex);
//			mutex_unlock(&wq_pool_mutex);
//			show_workqueue_state();
//			return;
//		}
//		raw_spin_unlock_irq(&pwq->pool->lock);
//	}
//	mutex_unlock(&wq->mutex);

//	/*
//	 * wq list is used to freeze wq, remove from list after
//	 * flushing is complete in case freeze races us.
//	 */
//	list_del_rcu(&wq->list);
//	mutex_unlock(&wq_pool_mutex);

//	if (!(wq->flags & WQ_UNBOUND)) {
//		wq_unregister_lockdep(wq);
//		/*
//		 * The base ref is never dropped on per-cpu pwqs.  Directly
//		 * schedule RCU free.
//		 */
//		call_rcu(&wq->rcu, rcu_free_wq);
//	} else {
//		/*
//		 * We're the sole accessor of @wq at this point.  Directly
//		 * access numa_pwq_tbl[] and dfl_pwq to put the base refs.
//		 * @wq will be freed when the last pwq is released.
//		 */
//		for_each_node(node) {
//			pwq = rcu_access_pointer(wq->numa_pwq_tbl[node]);
//			RCU_INIT_POINTER(wq->numa_pwq_tbl[node], NULL);
//			put_pwq_unlocked(pwq);
//		}

//		/*
//		 * Put dfl_pwq.  @wq may be freed any time after dfl_pwq is
//		 * put.  Don't access it afterwards.
//		 */
//		pwq = wq->dfl_pwq;
//		wq->dfl_pwq = NULL;
//		put_pwq_unlocked(pwq);
//	}
//}
//EXPORT_SYMBOL_GPL(destroy_workqueue);

///**
// * workqueue_set_max_active - adjust max_active of a workqueue
// * @wq: target workqueue
// * @max_active: new max_active value.
// *
// * Set max_active of @wq to @max_active.
// *
// * CONTEXT:
// * Don't call from IRQ context.
// */
//void workqueue_set_max_active(struct workqueue_struct *wq, int max_active)
//{
//	struct pool_workqueue *pwq;

//	/* disallow meddling with max_active for ordered workqueues */
//	if (WARN_ON(wq->flags & __WQ_ORDERED_EXPLICIT))
//		return;

//	max_active = wq_clamp_max_active(max_active, wq->flags, wq->name);

//	mutex_lock(&wq->mutex);

//	wq->flags &= ~__WQ_ORDERED;
//	wq->saved_max_active = max_active;

//	for_each_pwq(pwq, wq)
//		pwq_adjust_max_active(pwq);

//	mutex_unlock(&wq->mutex);
//}
//EXPORT_SYMBOL_GPL(workqueue_set_max_active);

///**
// * current_work - retrieve %current task's work struct
// *
// * Determine if %current task is a workqueue worker and what it's working on.
// * Useful to find out the context that the %current task is running in.
// *
// * Return: work struct if %current task is a workqueue worker, %NULL otherwise.
// */
//struct work_struct *current_work(void)
//{
//	struct worker *worker = current_wq_worker();

//	return worker ? worker->current_work : NULL;
//}
//EXPORT_SYMBOL(current_work);

///**
// * current_is_workqueue_rescuer - is %current workqueue rescuer?
// *
// * Determine whether %current is a workqueue rescuer.  Can be used from
// * work functions to determine whether it's being run off the rescuer task.
// *
// * Return: %true if %current is a workqueue rescuer. %false otherwise.
// */
//bool current_is_workqueue_rescuer(void)
//{
//	struct worker *worker = current_wq_worker();

//	return worker && worker->rescue_wq;
//}

///**
// * workqueue_congested - test whether a workqueue is congested
// * @cpu: CPU in question
// * @wq: target workqueue
// *
// * Test whether @wq's cpu workqueue for @cpu is congested.  There is
// * no synchronization around this function and the test result is
// * unreliable and only useful as advisory hints or for debugging.
// *
// * If @cpu is WORK_CPU_UNBOUND, the test is performed on the local CPU.
// * Note that both per-cpu and unbound workqueues may be associated with
// * multiple pool_workqueues which have separate congested states.  A
// * workqueue being congested on one CPU doesn't mean the workqueue is also
// * contested on other CPUs / NUMA nodes.
// *
// * Return:
// * %true if congested, %false otherwise.
// */
//bool workqueue_congested(int cpu, struct workqueue_struct *wq)
//{
//	struct pool_workqueue *pwq;
//	bool ret;

//	rcu_read_lock();
//	preempt_disable();

//	if (cpu == WORK_CPU_UNBOUND)
//		cpu = smp_processor_id();

//	if (!(wq->flags & WQ_UNBOUND))
//		pwq = per_cpu_ptr(wq->cpu_pwqs, cpu);
//	else
//		pwq = unbound_pwq_by_node(wq, cpu_to_node(cpu));

//	ret = !list_empty(&pwq->delayed_works);
//	preempt_enable();
//	rcu_read_unlock();

//	return ret;
//}
//EXPORT_SYMBOL_GPL(workqueue_congested);

///**
// * work_busy - test whether a work is currently pending or running
// * @work: the work to be tested
// *
// * Test whether @work is currently pending or running.  There is no
// * synchronization around this function and the test result is
// * unreliable and only useful as advisory hints or for debugging.
// *
// * Return:
// * OR'd bitmask of WORK_BUSY_* bits.
// */
//unsigned int work_busy(struct work_struct *work)
//{
//	struct worker_pool *pool;
//	unsigned long flags;
//	unsigned int ret = 0;

//	if (work_pending(work))
//		ret |= WORK_BUSY_PENDING;

//	rcu_read_lock();
//	pool = get_work_pool(work);
//	if (pool) {
//		raw_spin_lock_irqsave(&pool->lock, flags);
//		if (find_worker_executing_work(pool, work))
//			ret |= WORK_BUSY_RUNNING;
//		raw_spin_unlock_irqrestore(&pool->lock, flags);
//	}
//	rcu_read_unlock();

//	return ret;
//}
//EXPORT_SYMBOL_GPL(work_busy);

///**
// * set_worker_desc - set description for the current work item
// * @fmt: printf-style format string
// * @...: arguments for the format string
// *
// * This function can be called by a running work function to describe what
// * the work item is about.  If the worker task gets dumped, this
// * information will be printed out together to help debugging.  The
// * description can be at most WORKER_DESC_LEN including the trailing '\0'.
// */
//void set_worker_desc(const char *fmt, ...)
//{
//	struct worker *worker = current_wq_worker();
//	va_list args;

//	if (worker) {
//		va_start(args, fmt);
//		vsnprintf(worker->desc, sizeof(worker->desc), fmt, args);
//		va_end(args);
//	}
//}
//EXPORT_SYMBOL_GPL(set_worker_desc);

///**
// * print_worker_info - print out worker information and description
// * @log_lvl: the log level to use when printing
// * @task: target task
// *
// * If @task is a worker and currently executing a work item, print out the
// * name of the workqueue being serviced and worker description set with
// * set_worker_desc() by the currently executing work item.
// *
// * This function can be safely called on any task as long as the
// * task_struct itself is accessible.  While safe, this function isn't
// * synchronized and may print out mixups or garbages of limited length.
// */
//void print_worker_info(const char *log_lvl, struct task_struct *task)
//{
//	work_func_t *fn = NULL;
//	char name[WQ_NAME_LEN] = { };
//	char desc[WORKER_DESC_LEN] = { };
//	struct pool_workqueue *pwq = NULL;
//	struct workqueue_struct *wq = NULL;
//	struct worker *worker;

//	if (!(task->flags & PF_WQ_WORKER))
//		return;

//	/*
//	 * This function is called without any synchronization and @task
//	 * could be in any state.  Be careful with dereferences.
//	 */
//	worker = kthread_probe_data(task);

//	/*
//	 * Carefully copy the associated workqueue's workfn, name and desc.
//	 * Keep the original last '\0' in case the original is garbage.
//	 */
//	copy_from_kernel_nofault(&fn, &worker->current_func, sizeof(fn));
//	copy_from_kernel_nofault(&pwq, &worker->current_pwq, sizeof(pwq));
//	copy_from_kernel_nofault(&wq, &pwq->wq, sizeof(wq));
//	copy_from_kernel_nofault(name, wq->name, sizeof(name) - 1);
//	copy_from_kernel_nofault(desc, worker->desc, sizeof(desc) - 1);

//	if (fn || name[0] || desc[0]) {
//		printk("%sWorkqueue: %s %ps", log_lvl, name, fn);
//		if (strcmp(name, desc))
//			pr_cont(" (%s)", desc);
//		pr_cont("\n");
//	}
//}

//static void pr_cont_pool_info(struct worker_pool *pool)
//{
//	pr_cont(" cpus=%*pbl", nr_cpumask_bits, pool->attrs->cpumask);
//	if (pool->node != NUMA_NO_NODE)
//		pr_cont(" node=%d", pool->node);
//	pr_cont(" flags=0x%x nice=%d", pool->flags, pool->attrs->nice);
//}

//static void pr_cont_work(bool comma, struct work_struct *work)
//{
//	if (work->func == wq_barrier_func) {
//		struct wq_barrier *barr;

//		barr = container_of(work, struct wq_barrier, work);

//		pr_cont("%s BAR(%d)", comma ? "," : "",
//			task_pid_nr(barr->task));
//	} else {
//		pr_cont("%s %ps", comma ? "," : "", work->func);
//	}
//}

//static void show_pwq(struct pool_workqueue *pwq)
//{
//	struct worker_pool *pool = pwq->pool;
//	struct work_struct *work;
//	struct worker *worker;
//	bool has_in_flight = false, has_pending = false;
//	int bkt;

//	pr_info("  pwq %d:", pool->id);
//	pr_cont_pool_info(pool);

//	pr_cont(" active=%d/%d refcnt=%d%s\n",
//		pwq->nr_active, pwq->max_active, pwq->refcnt,
//		!list_empty(&pwq->mayday_node) ? " MAYDAY" : "");

//	hash_for_each(pool->busy_hash, bkt, worker, hentry) {
//		if (worker->current_pwq == pwq) {
//			has_in_flight = true;
//			break;
//		}
//	}
//	if (has_in_flight) {
//		bool comma = false;

//		pr_info("    in-flight:");
//		hash_for_each(pool->busy_hash, bkt, worker, hentry) {
//			if (worker->current_pwq != pwq)
//				continue;

//			pr_cont("%s %d%s:%ps", comma ? "," : "",
//				task_pid_nr(worker->task),
//				worker->rescue_wq ? "(RESCUER)" : "",
//				worker->current_func);
//			list_for_each_entry(work, &worker->scheduled, entry)
//				pr_cont_work(false, work);
//			comma = true;
//		}
//		pr_cont("\n");
//	}

//	list_for_each_entry(work, &pool->worklist, entry) {
//		if (get_work_pwq(work) == pwq) {
//			has_pending = true;
//			break;
//		}
//	}
//	if (has_pending) {
//		bool comma = false;

//		pr_info("    pending:");
//		list_for_each_entry(work, &pool->worklist, entry) {
//			if (get_work_pwq(work) != pwq)
//				continue;

//			pr_cont_work(comma, work);
//			comma = !(*work_data_bits(work) & WORK_STRUCT_LINKED);
//		}
//		pr_cont("\n");
//	}

//	if (!list_empty(&pwq->delayed_works)) {
//		bool comma = false;

//		pr_info("    delayed:");
//		list_for_each_entry(work, &pwq->delayed_works, entry) {
//			pr_cont_work(comma, work);
//			comma = !(*work_data_bits(work) & WORK_STRUCT_LINKED);
//		}
//		pr_cont("\n");
//	}
//}

///**
// * show_workqueue_state - dump workqueue state
// *
// * Called from a sysrq handler or try_to_freeze_tasks() and prints out
// * all busy workqueues and pools.
// */
//void show_workqueue_state(void)
//{
//	struct workqueue_struct *wq;
//	struct worker_pool *pool;
//	unsigned long flags;
//	int pi;

//	rcu_read_lock();

//	pr_info("Showing busy workqueues and worker pools:\n");

//	list_for_each_entry_rcu(wq, &workqueues, list) {
//		struct pool_workqueue *pwq;
//		bool idle = true;

//		for_each_pwq(pwq, wq) {
//			if (pwq->nr_active || !list_empty(&pwq->delayed_works)) {
//				idle = false;
//				break;
//			}
//		}
//		if (idle)
//			continue;

//		pr_info("workqueue %s: flags=0x%x\n", wq->name, wq->flags);

//		for_each_pwq(pwq, wq) {
//			raw_spin_lock_irqsave(&pwq->pool->lock, flags);
//			if (pwq->nr_active || !list_empty(&pwq->delayed_works))
//				show_pwq(pwq);
//			raw_spin_unlock_irqrestore(&pwq->pool->lock, flags);
//			/*
//			 * We could be printing a lot from atomic context, e.g.
//			 * sysrq-t -> show_workqueue_state(). Avoid triggering
//			 * hard lockup.
//			 */
//			touch_nmi_watchdog();
//		}
//	}

//	for_each_pool(pool, pi) {
//		struct worker *worker;
//		bool first = true;

//		raw_spin_lock_irqsave(&pool->lock, flags);
//		if (pool->nr_workers == pool->nr_idle)
//			goto next_pool;

//		pr_info("pool %d:", pool->id);
//		pr_cont_pool_info(pool);
//		pr_cont(" hung=%us workers=%d",
//			jiffies_to_msecs(jiffies - pool->watchdog_ts) / 1000,
//			pool->nr_workers);
//		if (pool->manager)
//			pr_cont(" manager: %d",
//				task_pid_nr(pool->manager->task));
//		list_for_each_entry(worker, &pool->idle_list, entry) {
//			pr_cont(" %s%d", first ? "idle: " : "",
//				task_pid_nr(worker->task));
//			first = false;
//		}
//		pr_cont("\n");
//	next_pool:
//		raw_spin_unlock_irqrestore(&pool->lock, flags);
//		/*
//		 * We could be printing a lot from atomic context, e.g.
//		 * sysrq-t -> show_workqueue_state(). Avoid triggering
//		 * hard lockup.
//		 */
//		touch_nmi_watchdog();
//	}

//	rcu_read_unlock();
//}

///* used to show worker information through /proc/PID/{comm,stat,status} */
//void wq_worker_comm(char *buf, size_t size, struct task_struct *task)
//{
//	int off;

//	/* always show the actual comm */
//	off = strscpy(buf, task->comm, size);
//	if (off < 0)
//		return;

//	/* stabilize PF_WQ_WORKER and worker pool association */
//	mutex_lock(&wq_pool_attach_mutex);

//	if (task->flags & PF_WQ_WORKER) {
//		struct worker *worker = kthread_data(task);
//		struct worker_pool *pool = worker->pool;

//		if (pool) {
//			raw_spin_lock_irq(&pool->lock);
//			/*
//			 * ->desc tracks information (wq name or
//			 * set_worker_desc()) for the latest execution.  If
//			 * current, prepend '+', otherwise '-'.
//			 */
//			if (worker->desc[0] != '\0') {
//				if (worker->current_work)
//					scnprintf(buf + off, size - off, "+%s",
//						  worker->desc);
//				else
//					scnprintf(buf + off, size - off, "-%s",
//						  worker->desc);
//			}
//			raw_spin_unlock_irq(&pool->lock);
//		}
//	}

//	mutex_unlock(&wq_pool_attach_mutex);
//}

//#ifdef CONFIG_SMP

///*
// * CPU hotplug.
// *
// * There are two challenges in supporting CPU hotplug.  Firstly, there
// * are a lot of assumptions on strong associations among work, pwq and
// * pool which make migrating pending and scheduled works very
// * difficult to implement without impacting hot paths.  Secondly,
// * worker pools serve mix of short, long and very long running works making
// * blocked draining impractical.
// *
// * This is solved by allowing the pools to be disassociated from the CPU
// * running as an unbound one and allowing it to be reattached later if the
// * cpu comes back online.
// */

//static void unbind_workers(int cpu)
//{
//	struct worker_pool *pool;
//	struct worker *worker;

//	for_each_cpu_worker_pool(pool, cpu) {
//		mutex_lock(&wq_pool_attach_mutex);
//		raw_spin_lock_irq(&pool->lock);

//		/*
//		 * We've blocked all attach/detach operations. Make all workers
//		 * unbound and set DISASSOCIATED.  Before this, all workers
//		 * except for the ones which are still executing works from
//		 * before the last CPU down must be on the cpu.  After
//		 * this, they may become diasporas.
//		 */
//		for_each_pool_worker(worker, pool)
//			worker->flags |= WORKER_UNBOUND;

//		pool->flags |= POOL_DISASSOCIATED;

//		raw_spin_unlock_irq(&pool->lock);
//		mutex_unlock(&wq_pool_attach_mutex);

//		/*
//		 * Call schedule() so that we cross rq->lock and thus can
//		 * guarantee sched callbacks see the %WORKER_UNBOUND flag.
//		 * This is necessary as scheduler callbacks may be invoked
//		 * from other cpus.
//		 */
//		schedule();

//		/*
//		 * Sched callbacks are disabled now.  Zap nr_running.
//		 * After this, nr_running stays zero and need_more_worker()
//		 * and keep_working() are always true as long as the
//		 * worklist is not empty.  This pool now behaves as an
//		 * unbound (in terms of concurrency management) pool which
//		 * are served by workers tied to the pool.
//		 */
//		atomic_set(&pool->nr_running, 0);

//		/*
//		 * With concurrency management just turned off, a busy
//		 * worker blocking could lead to lengthy stalls.  Kick off
//		 * unbound chain execution of currently pending work items.
//		 */
//		raw_spin_lock_irq(&pool->lock);
//		wake_up_worker(pool);
//		raw_spin_unlock_irq(&pool->lock);
//	}
//}

///**
// * rebind_workers - rebind all workers of a pool to the associated CPU
// * @pool: pool of interest
// *
// * @pool->cpu is coming online.  Rebind all workers to the CPU.
// */
//static void rebind_workers(struct worker_pool *pool)
//{
//	struct worker *worker;

//	lockdep_assert_held(&wq_pool_attach_mutex);

//	/*
//	 * Restore CPU affinity of all workers.  As all idle workers should
//	 * be on the run-queue of the associated CPU before any local
//	 * wake-ups for concurrency management happen, restore CPU affinity
//	 * of all workers first and then clear UNBOUND.  As we're called
//	 * from CPU_ONLINE, the following shouldn't fail.
//	 */
//	for_each_pool_worker(worker, pool)
//		WARN_ON_ONCE(set_cpus_allowed_ptr(worker->task,
//						  pool->attrs->cpumask) < 0);

//	raw_spin_lock_irq(&pool->lock);

//	pool->flags &= ~POOL_DISASSOCIATED;

//	for_each_pool_worker(worker, pool) {
//		unsigned int worker_flags = worker->flags;

//		/*
//		 * A bound idle worker should actually be on the runqueue
//		 * of the associated CPU for local wake-ups targeting it to
//		 * work.  Kick all idle workers so that they migrate to the
//		 * associated CPU.  Doing this in the same loop as
//		 * replacing UNBOUND with REBOUND is safe as no worker will
//		 * be bound before @pool->lock is released.
//		 */
//		if (worker_flags & WORKER_IDLE)
//			wake_up_process(worker->task);

//		/*
//		 * We want to clear UNBOUND but can't directly call
//		 * worker_clr_flags() or adjust nr_running.  Atomically
//		 * replace UNBOUND with another NOT_RUNNING flag REBOUND.
//		 * @worker will clear REBOUND using worker_clr_flags() when
//		 * it initiates the next execution cycle thus restoring
//		 * concurrency management.  Note that when or whether
//		 * @worker clears REBOUND doesn't affect correctness.
//		 *
//		 * WRITE_ONCE() is necessary because @worker->flags may be
//		 * tested without holding any lock in
//		 * wq_worker_running().  Without it, NOT_RUNNING test may
//		 * fail incorrectly leading to premature concurrency
//		 * management operations.
//		 */
//		WARN_ON_ONCE(!(worker_flags & WORKER_UNBOUND));
//		worker_flags |= WORKER_REBOUND;
//		worker_flags &= ~WORKER_UNBOUND;
//		WRITE_ONCE(worker->flags, worker_flags);
//	}

//	raw_spin_unlock_irq(&pool->lock);
//}

///**
// * restore_unbound_workers_cpumask - restore cpumask of unbound workers
// * @pool: unbound pool of interest
// * @cpu: the CPU which is coming up
// *
// * An unbound pool may end up with a cpumask which doesn't have any online
// * CPUs.  When a worker of such pool get scheduled, the scheduler resets
// * its cpus_allowed.  If @cpu is in @pool's cpumask which didn't have any
// * online CPU before, cpus_allowed of all its workers should be restored.
// */
//static void restore_unbound_workers_cpumask(struct worker_pool *pool, int cpu)
//{
//	static cpumask_t cpumask;
//	struct worker *worker;

//	lockdep_assert_held(&wq_pool_attach_mutex);

//	/* is @cpu allowed for @pool? */
//	if (!cpumask_test_cpu(cpu, pool->attrs->cpumask))
//		return;

//	cpumask_and(&cpumask, pool->attrs->cpumask, cpu_online_mask);

//	/* as we're called from CPU_ONLINE, the following shouldn't fail */
//	for_each_pool_worker(worker, pool)
//		WARN_ON_ONCE(set_cpus_allowed_ptr(worker->task, &cpumask) < 0);
//}

//int workqueue_prepare_cpu(unsigned int cpu)
//{
//	struct worker_pool *pool;

//	for_each_cpu_worker_pool(pool, cpu) {
//		if (pool->nr_workers)
//			continue;
//		if (!create_worker(pool))
//			return -ENOMEM;
//	}
//	return 0;
//}

//int workqueue_online_cpu(unsigned int cpu)
//{
//	struct worker_pool *pool;
//	struct workqueue_struct *wq;
//	int pi;

//	mutex_lock(&wq_pool_mutex);

//	for_each_pool(pool, pi) {
//		mutex_lock(&wq_pool_attach_mutex);

//		if (pool->cpu == cpu)
//			rebind_workers(pool);
//		else if (pool->cpu < 0)
//			restore_unbound_workers_cpumask(pool, cpu);

//		mutex_unlock(&wq_pool_attach_mutex);
//	}

//	/* update NUMA affinity of unbound workqueues */
//	list_for_each_entry(wq, &workqueues, list)
//		wq_update_unbound_numa(wq, cpu, true);

//	mutex_unlock(&wq_pool_mutex);
//	return 0;
//}

//int workqueue_offline_cpu(unsigned int cpu)
//{
//	struct workqueue_struct *wq;

//	/* unbinding per-cpu workers should happen on the local CPU */
//	if (WARN_ON(cpu != smp_processor_id()))
//		return -1;

//	unbind_workers(cpu);

//	/* update NUMA affinity of unbound workqueues */
//	mutex_lock(&wq_pool_mutex);
//	list_for_each_entry(wq, &workqueues, list)
//		wq_update_unbound_numa(wq, cpu, false);
//	mutex_unlock(&wq_pool_mutex);

//	return 0;
//}

//struct work_for_cpu {
//	struct work_struct work;
//	long (*fn)(void *);
//	void *arg;
//	long ret;
//};

//static void work_for_cpu_fn(struct work_struct *work)
//{
//	struct work_for_cpu *wfc = container_of(work, struct work_for_cpu, work);

//	wfc->ret = wfc->fn(wfc->arg);
//}

///**
// * work_on_cpu - run a function in thread context on a particular cpu
// * @cpu: the cpu to run on
// * @fn: the function to run
// * @arg: the function arg
// *
// * It is up to the caller to ensure that the cpu doesn't go offline.
// * The caller must not hold any locks which would prevent @fn from completing.
// *
// * Return: The value @fn returns.
// */
//long work_on_cpu(int cpu, long (*fn)(void *), void *arg)
//{
//	struct work_for_cpu wfc = { .fn = fn, .arg = arg };

//	INIT_WORK_ONSTACK(&wfc.work, work_for_cpu_fn);
//	schedule_work_on(cpu, &wfc.work);
//	flush_work(&wfc.work);
//	destroy_work_on_stack(&wfc.work);
//	return wfc.ret;
//}
//EXPORT_SYMBOL_GPL(work_on_cpu);

///**
// * work_on_cpu_safe - run a function in thread context on a particular cpu
// * @cpu: the cpu to run on
// * @fn:  the function to run
// * @arg: the function argument
// *
// * Disables CPU hotplug and calls work_on_cpu(). The caller must not hold
// * any locks which would prevent @fn from completing.
// *
// * Return: The value @fn returns.
// */
//long work_on_cpu_safe(int cpu, long (*fn)(void *), void *arg)
//{
//	long ret = -ENODEV;

//	get_online_cpus();
//	if (cpu_online(cpu))
//		ret = work_on_cpu(cpu, fn, arg);
//	put_online_cpus();
//	return ret;
//}
//EXPORT_SYMBOL_GPL(work_on_cpu_safe);
//#endif /* CONFIG_SMP */

//#ifdef CONFIG_FREEZER

///**
// * freeze_workqueues_begin - begin freezing workqueues
// *
// * Start freezing workqueues.  After this function returns, all freezable
// * workqueues will queue new works to their delayed_works list instead of
// * pool->worklist.
// *
// * CONTEXT:
// * Grabs and releases wq_pool_mutex, wq->mutex and pool->lock's.
// */
//void freeze_workqueues_begin(void)
//{
//	struct workqueue_struct *wq;
//	struct pool_workqueue *pwq;

//	mutex_lock(&wq_pool_mutex);

//	WARN_ON_ONCE(workqueue_freezing);
//	workqueue_freezing = true;

//	list_for_each_entry(wq, &workqueues, list) {
//		mutex_lock(&wq->mutex);
//		for_each_pwq(pwq, wq)
//			pwq_adjust_max_active(pwq);
//		mutex_unlock(&wq->mutex);
//	}

//	mutex_unlock(&wq_pool_mutex);
//}

///**
// * freeze_workqueues_busy - are freezable workqueues still busy?
// *
// * Check whether freezing is complete.  This function must be called
// * between freeze_workqueues_begin() and thaw_workqueues().
// *
// * CONTEXT:
// * Grabs and releases wq_pool_mutex.
// *
// * Return:
// * %true if some freezable workqueues are still busy.  %false if freezing
// * is complete.
// */
//bool freeze_workqueues_busy(void)
//{
//	bool busy = false;
//	struct workqueue_struct *wq;
//	struct pool_workqueue *pwq;

//	mutex_lock(&wq_pool_mutex);

//	WARN_ON_ONCE(!workqueue_freezing);

//	list_for_each_entry(wq, &workqueues, list) {
//		if (!(wq->flags & WQ_FREEZABLE))
//			continue;
//		/*
//		 * nr_active is monotonically decreasing.  It's safe
//		 * to peek without lock.
//		 */
//		rcu_read_lock();
//		for_each_pwq(pwq, wq) {
//			WARN_ON_ONCE(pwq->nr_active < 0);
//			if (pwq->nr_active) {
//				busy = true;
//				rcu_read_unlock();
//				goto out_unlock;
//			}
//		}
//		rcu_read_unlock();
//	}
//out_unlock:
//	mutex_unlock(&wq_pool_mutex);
//	return busy;
//}

///**
// * thaw_workqueues - thaw workqueues
// *
// * Thaw workqueues.  Normal queueing is restored and all collected
// * frozen works are transferred to their respective pool worklists.
// *
// * CONTEXT:
// * Grabs and releases wq_pool_mutex, wq->mutex and pool->lock's.
// */
//void thaw_workqueues(void)
//{
//	struct workqueue_struct *wq;
//	struct pool_workqueue *pwq;

//	mutex_lock(&wq_pool_mutex);

//	if (!workqueue_freezing)
//		goto out_unlock;

//	workqueue_freezing = false;

//	/* restore max_active and repopulate worklist */
//	list_for_each_entry(wq, &workqueues, list) {
//		mutex_lock(&wq->mutex);
//		for_each_pwq(pwq, wq)
//			pwq_adjust_max_active(pwq);
//		mutex_unlock(&wq->mutex);
//	}

//out_unlock:
//	mutex_unlock(&wq_pool_mutex);
//}
//#endif /* CONFIG_FREEZER */

//static int workqueue_apply_unbound_cpumask(void)
//{
//	LIST_HEAD(ctxs);
//	int ret = 0;
//	struct workqueue_struct *wq;
//	struct apply_wqattrs_ctx *ctx, *n;

//	lockdep_assert_held(&wq_pool_mutex);

//	list_for_each_entry(wq, &workqueues, list) {
//		if (!(wq->flags & WQ_UNBOUND))
//			continue;
//		/* creating multiple pwqs breaks ordering guarantee */
//		if (wq->flags & __WQ_ORDERED)
//			continue;

//		ctx = apply_wqattrs_prepare(wq, wq->unbound_attrs);
//		if (!ctx) {
//			ret = -ENOMEM;
//			break;
//		}

//		list_add_tail(&ctx->list, &ctxs);
//	}

//	list_for_each_entry_safe(ctx, n, &ctxs, list) {
//		if (!ret)
//			apply_wqattrs_commit(ctx);
//		apply_wqattrs_cleanup(ctx);
//	}

//	return ret;
//}

///**
// *  workqueue_set_unbound_cpumask - Set the low-level unbound cpumask
// *  @cpumask: the cpumask to set
// *
// *  The low-level workqueues cpumask is a global cpumask that limits
// *  the affinity of all unbound workqueues.  This function check the @cpumask
// *  and apply it to all unbound workqueues and updates all pwqs of them.
// *
// *  Retun:	0	- Success
// *  		-EINVAL	- Invalid @cpumask
// *  		-ENOMEM	- Failed to allocate memory for attrs or pwqs.
// */
//int workqueue_set_unbound_cpumask(cpumask_var_t cpumask)
//{
//	int ret = -EINVAL;
//	cpumask_var_t saved_cpumask;

//	if (!zalloc_cpumask_var(&saved_cpumask, GFP_KERNEL))
//		return -ENOMEM;

//	/*
//	 * Not excluding isolated cpus on purpose.
//	 * If the user wishes to include them, we allow that.
//	 */
//	cpumask_and(cpumask, cpumask, cpu_possible_mask);
//	if (!cpumask_empty(cpumask)) {
//		apply_wqattrs_lock();

//		/* save the old wq_unbound_cpumask. */
//		cpumask_copy(saved_cpumask, wq_unbound_cpumask);

//		/* update wq_unbound_cpumask at first and apply it to wqs. */
//		cpumask_copy(wq_unbound_cpumask, cpumask);
//		ret = workqueue_apply_unbound_cpumask();

//		/* restore the wq_unbound_cpumask when failed. */
//		if (ret < 0)
//			cpumask_copy(wq_unbound_cpumask, saved_cpumask);

//		apply_wqattrs_unlock();
//	}

//	free_cpumask_var(saved_cpumask);
//	return ret;
//}

//#ifdef CONFIG_SYSFS
///*
// * Workqueues with WQ_SYSFS flag set is visible to userland via
// * /sys/bus/workqueue/devices/WQ_NAME.  All visible workqueues have the
// * following attributes.
// *
// *  per_cpu	RO bool	: whether the workqueue is per-cpu or unbound
// *  max_active	RW int	: maximum number of in-flight work items
// *
// * Unbound workqueues have the following extra attributes.
// *
// *  pool_ids	RO int	: the associated pool IDs for each node
// *  nice	RW int	: nice value of the workers
// *  cpumask	RW mask	: bitmask of allowed CPUs for the workers
// *  numa	RW bool	: whether enable NUMA affinity
// */
//struct wq_device {
//	struct workqueue_struct		*wq;
//	struct device			dev;
//};

//static struct workqueue_struct *dev_to_wq(struct device *dev)
//{
//	struct wq_device *wq_dev = container_of(dev, struct wq_device, dev);

//	return wq_dev->wq;
//}

//static ssize_t per_cpu_show(struct device *dev, struct device_attribute *attr,
//			    char *buf)
//{
//	struct workqueue_struct *wq = dev_to_wq(dev);

//	return scnprintf(buf, PAGE_SIZE, "%d\n", (bool)!(wq->flags & WQ_UNBOUND));
//}
//static DEVICE_ATTR_RO(per_cpu);

//static ssize_t max_active_show(struct device *dev,
//			       struct device_attribute *attr, char *buf)
//{
//	struct workqueue_struct *wq = dev_to_wq(dev);

//	return scnprintf(buf, PAGE_SIZE, "%d\n", wq->saved_max_active);
//}

//static ssize_t max_active_store(struct device *dev,
//				struct device_attribute *attr, const char *buf,
//				size_t count)
//{
//	struct workqueue_struct *wq = dev_to_wq(dev);
//	int val;

//	if (sscanf(buf, "%d", &val) != 1 || val <= 0)
//		return -EINVAL;

//	workqueue_set_max_active(wq, val);
//	return count;
//}
//static DEVICE_ATTR_RW(max_active);

//static struct attribute *wq_sysfs_attrs[] = {
//	&dev_attr_per_cpu.attr,
//	&dev_attr_max_active.attr,
//	NULL,
//};
//ATTRIBUTE_GROUPS(wq_sysfs);

//static ssize_t wq_pool_ids_show(struct device *dev,
//				struct device_attribute *attr, char *buf)
//{
//	struct workqueue_struct *wq = dev_to_wq(dev);
//	const char *delim = "";
//	int node, written = 0;

//	get_online_cpus();
//	rcu_read_lock();
//	for_each_node(node) {
//		written += scnprintf(buf + written, PAGE_SIZE - written,
//				     "%s%d:%d", delim, node,
//				     unbound_pwq_by_node(wq, node)->pool->id);
//		delim = " ";
//	}
//	written += scnprintf(buf + written, PAGE_SIZE - written, "\n");
//	rcu_read_unlock();
//	put_online_cpus();

//	return written;
//}

//static ssize_t wq_nice_show(struct device *dev, struct device_attribute *attr,
//			    char *buf)
//{
//	struct workqueue_struct *wq = dev_to_wq(dev);
//	int written;

//	mutex_lock(&wq->mutex);
//	written = scnprintf(buf, PAGE_SIZE, "%d\n", wq->unbound_attrs->nice);
//	mutex_unlock(&wq->mutex);

//	return written;
//}

///* prepare workqueue_attrs for sysfs store operations */
//static struct workqueue_attrs *wq_sysfs_prep_attrs(struct workqueue_struct *wq)
//{
//	struct workqueue_attrs *attrs;

//	lockdep_assert_held(&wq_pool_mutex);

//	attrs = alloc_workqueue_attrs();
//	if (!attrs)
//		return NULL;

//	copy_workqueue_attrs(attrs, wq->unbound_attrs);
//	return attrs;
//}

//static ssize_t wq_nice_store(struct device *dev, struct device_attribute *attr,
//			     const char *buf, size_t count)
//{
//	struct workqueue_struct *wq = dev_to_wq(dev);
//	struct workqueue_attrs *attrs;
//	int ret = -ENOMEM;

//	apply_wqattrs_lock();

//	attrs = wq_sysfs_prep_attrs(wq);
//	if (!attrs)
//		goto out_unlock;

//	if (sscanf(buf, "%d", &attrs->nice) == 1 &&
//	    attrs->nice >= MIN_NICE && attrs->nice <= MAX_NICE)
//		ret = apply_workqueue_attrs_locked(wq, attrs);
//	else
//		ret = -EINVAL;

//out_unlock:
//	apply_wqattrs_unlock();
//	free_workqueue_attrs(attrs);
//	return ret ?: count;
//}

//static ssize_t wq_cpumask_show(struct device *dev,
//			       struct device_attribute *attr, char *buf)
//{
//	struct workqueue_struct *wq = dev_to_wq(dev);
//	int written;

//	mutex_lock(&wq->mutex);
//	written = scnprintf(buf, PAGE_SIZE, "%*pb\n",
//			    cpumask_pr_args(wq->unbound_attrs->cpumask));
//	mutex_unlock(&wq->mutex);
//	return written;
//}

//static ssize_t wq_cpumask_store(struct device *dev,
//				struct device_attribute *attr,
//				const char *buf, size_t count)
//{
//	struct workqueue_struct *wq = dev_to_wq(dev);
//	struct workqueue_attrs *attrs;
//	int ret = -ENOMEM;

//	apply_wqattrs_lock();

//	attrs = wq_sysfs_prep_attrs(wq);
//	if (!attrs)
//		goto out_unlock;

//	ret = cpumask_parse(buf, attrs->cpumask);
//	if (!ret)
//		ret = apply_workqueue_attrs_locked(wq, attrs);

//out_unlock:
//	apply_wqattrs_unlock();
//	free_workqueue_attrs(attrs);
//	return ret ?: count;
//}

//static ssize_t wq_numa_show(struct device *dev, struct device_attribute *attr,
//			    char *buf)
//{
//	struct workqueue_struct *wq = dev_to_wq(dev);
//	int written;

//	mutex_lock(&wq->mutex);
//	written = scnprintf(buf, PAGE_SIZE, "%d\n",
//			    !wq->unbound_attrs->no_numa);
//	mutex_unlock(&wq->mutex);

//	return written;
//}

//static ssize_t wq_numa_store(struct device *dev, struct device_attribute *attr,
//			     const char *buf, size_t count)
//{
//	struct workqueue_struct *wq = dev_to_wq(dev);
//	struct workqueue_attrs *attrs;
//	int v, ret = -ENOMEM;

//	apply_wqattrs_lock();

//	attrs = wq_sysfs_prep_attrs(wq);
//	if (!attrs)
//		goto out_unlock;

//	ret = -EINVAL;
//	if (sscanf(buf, "%d", &v) == 1) {
//		attrs->no_numa = !v;
//		ret = apply_workqueue_attrs_locked(wq, attrs);
//	}

//out_unlock:
//	apply_wqattrs_unlock();
//	free_workqueue_attrs(attrs);
//	return ret ?: count;
//}

//static struct device_attribute wq_sysfs_unbound_attrs[] = {
//	__ATTR(pool_ids, 0444, wq_pool_ids_show, NULL),
//	__ATTR(nice, 0644, wq_nice_show, wq_nice_store),
//	__ATTR(cpumask, 0644, wq_cpumask_show, wq_cpumask_store),
//	__ATTR(numa, 0644, wq_numa_show, wq_numa_store),
//	__ATTR_NULL,
//};

//static struct bus_type wq_subsys = {
//	.name				= "workqueue",
//	.dev_groups			= wq_sysfs_groups,
//};

//static ssize_t wq_unbound_cpumask_show(struct device *dev,
//		struct device_attribute *attr, char *buf)
//{
//	int written;

//	mutex_lock(&wq_pool_mutex);
//	written = scnprintf(buf, PAGE_SIZE, "%*pb\n",
//			    cpumask_pr_args(wq_unbound_cpumask));
//	mutex_unlock(&wq_pool_mutex);

//	return written;
//}

//static ssize_t wq_unbound_cpumask_store(struct device *dev,
//		struct device_attribute *attr, const char *buf, size_t count)
//{
//	cpumask_var_t cpumask;
//	int ret;

//	if (!zalloc_cpumask_var(&cpumask, GFP_KERNEL))
//		return -ENOMEM;

//	ret = cpumask_parse(buf, cpumask);
//	if (!ret)
//		ret = workqueue_set_unbound_cpumask(cpumask);

//	free_cpumask_var(cpumask);
//	return ret ? ret : count;
//}

//static struct device_attribute wq_sysfs_cpumask_attr =
//	__ATTR(cpumask, 0644, wq_unbound_cpumask_show,
//	       wq_unbound_cpumask_store);

//static int __init wq_sysfs_init(void)
//{
//	int err;

//	err = subsys_virtual_register(&wq_subsys, NULL);
//	if (err)
//		return err;

//	return device_create_file(wq_subsys.dev_root, &wq_sysfs_cpumask_attr);
//}
//core_initcall(wq_sysfs_init);

//static void wq_device_release(struct device *dev)
//{
//	struct wq_device *wq_dev = container_of(dev, struct wq_device, dev);

//	kfree(wq_dev);
//}

///**
// * workqueue_sysfs_register - make a workqueue visible in sysfs
// * @wq: the workqueue to register
// *
// * Expose @wq in sysfs under /sys/bus/workqueue/devices.
// * alloc_workqueue*() automatically calls this function if WQ_SYSFS is set
// * which is the preferred method.
// *
// * Workqueue user should use this function directly iff it wants to apply
// * workqueue_attrs before making the workqueue visible in sysfs; otherwise,
// * apply_workqueue_attrs() may race against userland updating the
// * attributes.
// *
// * Return: 0 on success, -errno on failure.
// */
//int workqueue_sysfs_register(struct workqueue_struct *wq)
//{
//	struct wq_device *wq_dev;
//	int ret;

//	/*
//	 * Adjusting max_active or creating new pwqs by applying
//	 * attributes breaks ordering guarantee.  Disallow exposing ordered
//	 * workqueues.
//	 */
//	if (WARN_ON(wq->flags & __WQ_ORDERED_EXPLICIT))
//		return -EINVAL;

//	wq->wq_dev = wq_dev = kzalloc(sizeof(*wq_dev), GFP_KERNEL);
//	if (!wq_dev)
//		return -ENOMEM;

//	wq_dev->wq = wq;
//	wq_dev->dev.bus = &wq_subsys;
//	wq_dev->dev.release = wq_device_release;
//	dev_set_name(&wq_dev->dev, "%s", wq->name);

//	/*
//	 * unbound_attrs are created separately.  Suppress uevent until
//	 * everything is ready.
//	 */
//	dev_set_uevent_suppress(&wq_dev->dev, true);

//	ret = device_register(&wq_dev->dev);
//	if (ret) {
//		put_device(&wq_dev->dev);
//		wq->wq_dev = NULL;
//		return ret;
//	}

//	if (wq->flags & WQ_UNBOUND) {
//		struct device_attribute *attr;

//		for (attr = wq_sysfs_unbound_attrs; attr->attr.name; attr++) {
//			ret = device_create_file(&wq_dev->dev, attr);
//			if (ret) {
//				device_unregister(&wq_dev->dev);
//				wq->wq_dev = NULL;
//				return ret;
//			}
//		}
//	}

//	dev_set_uevent_suppress(&wq_dev->dev, false);
//	kobject_uevent(&wq_dev->dev.kobj, KOBJ_ADD);
//	return 0;
//}

///**
// * workqueue_sysfs_unregister - undo workqueue_sysfs_register()
// * @wq: the workqueue to unregister
// *
// * If @wq is registered to sysfs by workqueue_sysfs_register(), unregister.
// */
//static void workqueue_sysfs_unregister(struct workqueue_struct *wq)
//{
//	struct wq_device *wq_dev = wq->wq_dev;

//	if (!wq->wq_dev)
//		return;

//	wq->wq_dev = NULL;
//	device_unregister(&wq_dev->dev);
//}
//#else	/* CONFIG_SYSFS */
//static void workqueue_sysfs_unregister(struct workqueue_struct *wq)	{ }
//#endif	/* CONFIG_SYSFS */

///*
// * Workqueue watchdog.
// *
// * Stall may be caused by various bugs - missing WQ_MEM_RECLAIM, illegal
// * flush dependency, a concurrency managed work item which stays RUNNING
// * indefinitely.  Workqueue stalls can be very difficult to debug as the
// * usual warning mechanisms don't trigger and internal workqueue state is
// * largely opaque.
// *
// * Workqueue watchdog monitors all worker pools periodically and dumps
// * state if some pools failed to make forward progress for a while where
// * forward progress is defined as the first item on ->worklist changing.
// *
// * This mechanism is controlled through the kernel parameter
// * "workqueue.watchdog_thresh" which can be updated at runtime through the
// * corresponding sysfs parameter file.
// */
//#ifdef CONFIG_WQ_WATCHDOG

//static unsigned long wq_watchdog_thresh = 30;
//static struct timer_list wq_watchdog_timer;

//static unsigned long wq_watchdog_touched = INITIAL_JIFFIES;
//static DEFINE_PER_CPU(unsigned long, wq_watchdog_touched_cpu) = INITIAL_JIFFIES;

//static void wq_watchdog_reset_touched(void)
//{
//	int cpu;

//	wq_watchdog_touched = jiffies;
//	for_each_possible_cpu(cpu)
//		per_cpu(wq_watchdog_touched_cpu, cpu) = jiffies;
//}

//static void wq_watchdog_timer_fn(struct timer_list *unused)
//{
//	unsigned long thresh = READ_ONCE(wq_watchdog_thresh) * HZ;
//	bool lockup_detected = false;
//	unsigned long now = jiffies;
//	struct worker_pool *pool;
//	int pi;

//	if (!thresh)
//		return;

//	rcu_read_lock();

//	for_each_pool(pool, pi) {
//		unsigned long pool_ts, touched, ts;

//		if (list_empty(&pool->worklist))
//			continue;

//		/*
//		 * If a virtual machine is stopped by the host it can look to
//		 * the watchdog like a stall.
//		 */
//		kvm_check_and_clear_guest_paused();

//		/* get the latest of pool and touched timestamps */
//		pool_ts = READ_ONCE(pool->watchdog_ts);
//		touched = READ_ONCE(wq_watchdog_touched);

//		if (time_after(pool_ts, touched))
//			ts = pool_ts;
//		else
//			ts = touched;

//		if (pool->cpu >= 0) {
//			unsigned long cpu_touched =
//				READ_ONCE(per_cpu(wq_watchdog_touched_cpu,
//						  pool->cpu));
//			if (time_after(cpu_touched, ts))
//				ts = cpu_touched;
//		}

//		/* did we stall? */
//		if (time_after(now, ts + thresh)) {
//			lockup_detected = true;
//			pr_emerg("BUG: workqueue lockup - pool");
//			pr_cont_pool_info(pool);
//			pr_cont(" stuck for %us!\n",
//				jiffies_to_msecs(now - pool_ts) / 1000);
//		}
//	}

//	rcu_read_unlock();

//	if (lockup_detected)
//		show_workqueue_state();

//	wq_watchdog_reset_touched();
//	mod_timer(&wq_watchdog_timer, jiffies + thresh);
//}

//notrace void wq_watchdog_touch(int cpu)
//{
//	if (cpu >= 0)
//		per_cpu(wq_watchdog_touched_cpu, cpu) = jiffies;
//	else
//		wq_watchdog_touched = jiffies;
//}

//static void wq_watchdog_set_thresh(unsigned long thresh)
//{
//	wq_watchdog_thresh = 0;
//	del_timer_sync(&wq_watchdog_timer);

//	if (thresh) {
//		wq_watchdog_thresh = thresh;
//		wq_watchdog_reset_touched();
//		mod_timer(&wq_watchdog_timer, jiffies + thresh * HZ);
//	}
//}

//static int wq_watchdog_param_set_thresh(const char *val,
//					const struct kernel_param *kp)
//{
//	unsigned long thresh;
//	int ret;

//	ret = kstrtoul(val, 0, &thresh);
//	if (ret)
//		return ret;

//	if (system_wq)
//		wq_watchdog_set_thresh(thresh);
//	else
//		wq_watchdog_thresh = thresh;

//	return 0;
//}

//static const struct kernel_param_ops wq_watchdog_thresh_ops = {
//	.set	= wq_watchdog_param_set_thresh,
//	.get	= param_get_ulong,
//};

//module_param_cb(watchdog_thresh, &wq_watchdog_thresh_ops, &wq_watchdog_thresh,
//		0644);

//static void wq_watchdog_init(void)
//{
//	timer_setup(&wq_watchdog_timer, wq_watchdog_timer_fn, TIMER_DEFERRABLE);
//	wq_watchdog_set_thresh(wq_watchdog_thresh);
//}

//#else	/* CONFIG_WQ_WATCHDOG */

//static inline void wq_watchdog_init(void) { }

//#endif	/* CONFIG_WQ_WATCHDOG */

//static void __init wq_numa_init(void)
//{
//	cpumask_var_t *tbl;
//	int node, cpu;

//	if (num_possible_nodes() <= 1)
//		return;

//	if (wq_disable_numa) {
//		pr_info("workqueue: NUMA affinity support disabled\n");
//		return;
//	}

//	wq_update_unbound_numa_attrs_buf = alloc_workqueue_attrs();
//	BUG_ON(!wq_update_unbound_numa_attrs_buf);

//	/*
//	 * We want masks of possible CPUs of each node which isn't readily
//	 * available.  Build one from cpu_to_node() which should have been
//	 * fully initialized by now.
//	 */
//	tbl = kcalloc(nr_node_ids, sizeof(tbl[0]), GFP_KERNEL);
//	BUG_ON(!tbl);

//	for_each_node(node)
//		BUG_ON(!zalloc_cpumask_var_node(&tbl[node], GFP_KERNEL,
//				node_online(node) ? node : NUMA_NO_NODE));

//	for_each_possible_cpu(cpu) {
//		node = cpu_to_node(cpu);
//		if (WARN_ON(node == NUMA_NO_NODE)) {
//			pr_warn("workqueue: NUMA node mapping not available for cpu%d, disabling NUMA support\n", cpu);
//			/* happens iff arch is bonkers, let's just proceed */
//			return;
//		}
//		cpumask_set_cpu(cpu, tbl[node]);
//	}

//	wq_numa_possible_cpumask = tbl;
//	wq_numa_enabled = true;
//}

///**
// * workqueue_init_early - early init for workqueue subsystem
// *
// * This is the first half of two-staged workqueue subsystem initialization
// * and invoked as soon as the bare basics - memory allocation, cpumasks and
// * idr are up.  It sets up all the data structures and system workqueues
// * and allows early boot code to create workqueues and queue/cancel work
// * items.  Actual work item execution starts only after kthreads can be
// * created and scheduled right before early initcalls.
// */
//void __init workqueue_init_early(void)
//{
//	int std_nice[NR_STD_WORKER_POOLS] = { 0, HIGHPRI_NICE_LEVEL };
//	int hk_flags = HK_FLAG_DOMAIN | HK_FLAG_WQ;
//	int i, cpu;

//	BUILD_BUG_ON(__alignof__(struct pool_workqueue) < __alignof__(long long));

//	BUG_ON(!alloc_cpumask_var(&wq_unbound_cpumask, GFP_KERNEL));
//	cpumask_copy(wq_unbound_cpumask, housekeeping_cpumask(hk_flags));

//	pwq_cache = KMEM_CACHE(pool_workqueue, SLAB_PANIC);

//	/* initialize CPU pools */
//	for_each_possible_cpu(cpu) {
//		struct worker_pool *pool;

//		i = 0;
//		for_each_cpu_worker_pool(pool, cpu) {
//			BUG_ON(init_worker_pool(pool));
//			pool->cpu = cpu;
//			cpumask_copy(pool->attrs->cpumask, cpumask_of(cpu));
//			pool->attrs->nice = std_nice[i++];
//			pool->node = cpu_to_node(cpu);

//			/* alloc pool ID */
//			mutex_lock(&wq_pool_mutex);
//			BUG_ON(worker_pool_assign_id(pool));
//			mutex_unlock(&wq_pool_mutex);
//		}
//	}

//	/* create default unbound and ordered wq attrs */
//	for (i = 0; i < NR_STD_WORKER_POOLS; i++) {
//		struct workqueue_attrs *attrs;

//		BUG_ON(!(attrs = alloc_workqueue_attrs()));
//		attrs->nice = std_nice[i];
//		unbound_std_wq_attrs[i] = attrs;

//		/*
//		 * An ordered wq should have only one pwq as ordering is
//		 * guaranteed by max_active which is enforced by pwqs.
//		 * Turn off NUMA so that dfl_pwq is used for all nodes.
//		 */
//		BUG_ON(!(attrs = alloc_workqueue_attrs()));
//		attrs->nice = std_nice[i];
//		attrs->no_numa = true;
//		ordered_wq_attrs[i] = attrs;
//	}

//	system_wq = alloc_workqueue("events", 0, 0);
//	system_highpri_wq = alloc_workqueue("events_highpri", WQ_HIGHPRI, 0);
//	system_long_wq = alloc_workqueue("events_long", 0, 0);
//	system_unbound_wq = alloc_workqueue("events_unbound", WQ_UNBOUND,
//					    WQ_UNBOUND_MAX_ACTIVE);
//	system_freezable_wq = alloc_workqueue("events_freezable",
//					      WQ_FREEZABLE, 0);
//	system_power_efficient_wq = alloc_workqueue("events_power_efficient",
//					      WQ_POWER_EFFICIENT, 0);
//	system_freezable_power_efficient_wq = alloc_workqueue("events_freezable_power_efficient",
//					      WQ_FREEZABLE | WQ_POWER_EFFICIENT,
//					      0);
//	BUG_ON(!system_wq || !system_highpri_wq || !system_long_wq ||
//	       !system_unbound_wq || !system_freezable_wq ||
//	       !system_power_efficient_wq ||
//	       !system_freezable_power_efficient_wq);
//}

///**
// * workqueue_init - bring workqueue subsystem fully online
// *
// * This is the latter half of two-staged workqueue subsystem initialization
// * and invoked as soon as kthreads can be created and scheduled.
// * Workqueues have been created and work items queued on them, but there
// * are no kworkers executing the work items yet.  Populate the worker pools
// * with the initial workers and enable future kworker creations.
// */
//void __init workqueue_init(void)
//{
//	struct workqueue_struct *wq;
//	struct worker_pool *pool;
//	int cpu, bkt;

//	/*
//	 * It'd be simpler to initialize NUMA in workqueue_init_early() but
//	 * CPU to node mapping may not be available that early on some
//	 * archs such as power and arm64.  As per-cpu pools created
//	 * previously could be missing node hint and unbound pools NUMA
//	 * affinity, fix them up.
//	 *
//	 * Also, while iterating workqueues, create rescuers if requested.
//	 */
//	wq_numa_init();

//	mutex_lock(&wq_pool_mutex);

//	for_each_possible_cpu(cpu) {
//		for_each_cpu_worker_pool(pool, cpu) {
//			pool->node = cpu_to_node(cpu);
//		}
//	}

//	list_for_each_entry(wq, &workqueues, list) {
//		wq_update_unbound_numa(wq, smp_processor_id(), true);
//		WARN(init_rescuer(wq),
//		     "workqueue: failed to create early rescuer for %s",
//		     wq->name);
//	}

//	mutex_unlock(&wq_pool_mutex);

//	/* create the initial workers */
//	for_each_online_cpu(cpu) {
//		for_each_cpu_worker_pool(pool, cpu) {
//			pool->flags &= ~POOL_DISASSOCIATED;
//			BUG_ON(!create_worker(pool));
//		}
//	}

//	hash_for_each(unbound_pool_hash, bkt, pool, hash_node)
//		BUG_ON(!create_worker(pool));

//	wq_online = true;
//	wq_watchdog_init();
//}
